Showing posts with label geology. Show all posts
Showing posts with label geology. Show all posts

Wednesday, June 5, 2019

The Map That Changed the World by Simon Winchester


Source of book: I own this.

 


The history of beliefs about the age of the earth make for an interesting pattern. Every culture has its own origin tales and creation stories. My eldest had to read a bunch of them for literature last year, in fact, and found them fascinating. While not about creation myths exclusively, Joseph Campbell’s The Hero With A Thousand Faces paints a fascinating picture of the similarities and their likely origin in the human psyche. After all, we have an innate need to understand our origins - and perhaps even more so, to understand our purpose. To this end, we write origin stories.

The evidence is strong that the ancients didn’t view truth as primarily empirical data. This is why even a good historian such as Herodotus places obviously fictional scenes in his histories. The point wasn’t so much “accuracy” as we moderns would understand it, but the narrative itself. The stories have meaning, and that meaning isn’t primarily literal. What a war means to the people who tells of it therefore will tend to win out over truth in many cases. (See the Lost Cause Myth, for a modern American example.) One can easily draw an analogy to creation myths as well. They are told, not so much for their scientific accuracy, but because they make a point that is meaningful to the culture in which they are told. Thus, even within a culture, the stories are not expected to be literally, factually true, but that they tell a truth about human existence.

Let me give an example: the kids and I have been touring the Western national parks over the last few years. The American Southwest is one of the last places in our nation where Native American historical sites have been preserved, along with the cultures which birthed them. Many of the sites have taken the time to find storytellers of the old myths, and the videos which resulted are fascinating. (In particular, Mesa Verde National Park has an extensive collection on video and in print on the origin myths told past and present by the builders of the Ancestral Pueblo civilization and their descendents.)

But here is the thing: as far as I can tell, most of the storytellers don’t believe that humans literally crawled out of a hole in the ground from the underworld. To make that literal idea the point of the myth is silly - and cheapens it. It’s like the person who tries to reduce a symphony to the mathematical calculation of the frequencies.

This is why, in my view, ancient peoples were not as wedded to our modern understanding of factual truth like we are. While the Genesis creation stories (and yes, there are two contradictory stories in the first two chapters) may reflect a genuine Ancient Near East belief about creation and the structure of the universe, I am not necessarily convinced that the editors who assembled the Old Testament during and after the exile believed every word to be factual truth. In fact, I think they would have given a truly awkward look at someone who insisted on that.

Having been raised Fundamentalist (in the cultural sense as well as the doctrinal sense), it was rather a surprise to me to discover a number of years ago that a literal reading of Genesis is actually a modern affectation, and most assuredly NOT the historical view of the Church. None less than St. Augustine warned against Christians making total fools of themselves by asserting literal interpretations that conflicted with scientific discoveries.

Well, what happened then? As the Middle Ages gave way to the so-called Modern era, a new approach to science started to take hold. In contrast to the Ancient Greek approach - abstract thought rather than messy experimentation and testing - a new scientific method based on observation, objectivity, and reproducible experiments became the norm. Along with that came a belief in reason rather than dogma. We call this (and related developments) The Enlightenment. While there is evidence that The Enlightenment was a mixed bag, like any human school of thought, it certainly changed the world, in many ways for the better.

The problem came when theologians decided to approach the ancient text of the Bible using Enlightenment tools. Instead of seeing the creation myths as holding spiritual and poetic truths, they……….did math.

While he wasn’t the first, James Ussher was the one who most definitely fixed the date of creation. (In case you wondered, it was the year 4004 BCE, on Monday, October 23, at precisely 9:00 AM. God is apparently not a morning person.) Yeah, feel free to laugh a bit at the pseudo-precision.

Sadly, Ussher’s view soon became the dominant belief in “Christian” Europe and America - displacing the older viewpoint.

It is with this background that Simon Winchester begins his story of one of the lesser-known names in modern science: William Smith, the father of English geology.

Smith was born in humble circumstances, but had a sharp mind for both figures and practical engineering. He embarked on a successful career as an engineer, focusing on drainage, coal mining, and canals. As a result, he came in direct contact with the various strata of rock underlying England. He was astute enough to notice that the rocks were always in the same order, regardless of where along the uplift band you were, and the fossils found in those rocks were predictable based on the stratum they were found in.

This ended up being the foundation on which the science of geology would rest. Smith’s work laid the foundation for Charles Lyell’s revolutionary theories, which in turn led to Darwin, and so on.

Smith is best known for his map - the one of the title - which is considered the first geologic map ever created. He spent 15 years working on it - which mean many, many miles of walking throughout England, taking samples, and comparing them. No drones or satellites were at his disposal, and the railroads and canals didn’t reach most of the places he needed to visit. So it was either an expensive horse-drawn conveyance, or, more often, his feet.

Smith’s story is a bit tragic in a way, however. Because he was a commoner, he was disrespected by many of the geologists of his day - who were part of the aristocracy. He was denied membership in the official society. But worse was the fact that his maps were brazenly plagiarized, undercutting his sales, and keeping him in relative obscurity. A combination of this and some poor financial decisions eventually led him to debtor’s prison.

Fortunately, after that, his life improved. He was recognized by the next generation of geologists as an important figure. His aristocratic rivals fell out of favor, and he was eventually given a pension by the Society so he could live out his twilight years in comfort.

As usual, Simon Winchester tells a compelling story, with just enough background information mixed in with the biographical to paint a complete picture. His writing is also rather good, adding to the experience, and making the arcane details interesting.

One observation in the book really struck me. In describing Smith’s humble background, but also his access to education - a relatively new thing in the 18th Century - he points out an argument which is still being used today by the privileged classes.

No matter the outcry that allowing the working classes to become educated was to debauch them and tempt them to abandon the manual labors for which they were best suited. “Nineteen in twenty of the species were designed by nature for trade and manufacture,” said a writer in The Grub-Street Journal at the time of Smith’s birth. “To take them off to read books is the way to do them harm, to make them not wiser or better, but impertinent, troublesome and factious.”

This was, of course, the argument during the Jim Crow era for why African Americans shouldn’t be educated at public expense. And it still continues today - I hear it from white right-wingers as an argument against diversity programs for higher education, and in the dismissive “they should be working another job if they have time to have sex” trope. At the heart, there is a belief that those at the lower strata of society should just accept their lot, their oppression, and be grateful that the upper class doesn’t starve them to death. Perhaps that is why education makes people “uppity”...

Winchester also makes a statement that really resonates with me. My first real break with my Fundamentalist upbringing occurred while I was still a child, and first understood the distances of stars. As we have been able to calculate stellar distances, the size of the universe has grown dramatically. (For how we calculate these distances, see How Old Is The Universe? by David Weintraub.) From there, it was easy to pivot to geology. In the American Southwest, the strata are pretty easy to see - as are the fossils. It is unmistakable that sediments have layers, and that they occur in particular orders. And that the fossils are consistent throughout the world. Here is Winchester on the revolutionary meaning of this discovery.

For the first time the earth had a provable history, a written record that paid no heed or obeisance to religious teaching and dogma, that declared its independence from the kind of faith that is no more than the blind acceptance of absurdity.

The blind acceptance of absurdity - and that is what so much of Evangelicalism is about these days. And not just regarding science. Whether it is the belief in the congenital inferiority of women, the persecution of sexual minorities, or vicious tribalism, to be Evangelical is to, of necessity, have faith that is blind acceptance of the absurd.

Here is St. Augustine, in words which ring true today:

It is too disgraceful and ruinous, though, and greatly to be avoided, that he [the non-Christian] should hear a Christian speaking so idiotically on these matters, and as if in accord with Christian writings, that he might say that he could scarcely keep from laughing when he saw how totally in error they are.
   
The more things change…

Before creating the map, Smith intended to write a book. For various reasons, this never happened. (Which is probably a good thing. While Smith was brilliant in many ways, his writing was boring as heck.) I mention this in part because the prospectus contained this Alexander Pope epigram:

All Nature is but Art Unknown to Thee.
All Chance, Direction which thou canst not see.

While there are a number of secondary characters in the book who played important roles in the story, there are two I specifically wanted to mention. First is Smith’s archrival, George Bellas Greenough, who formed a perfect foil for Smith. Greenough was of the old school, where geology (and science in general) was meant to be done by thinking and writing, not field work. That sort of thing was for the common laborers. Like Smith. It was Greenough who plagiarized Smith’s work, and who kept Smith out of the Geological Society for decades. It wasn’t until he lost his grip on power that Smith was able to be recognized. A great line about Greenough was that he was thought to have a second-rate mind but first-rate connections.

The second character is that of Sir Joseph Banks, a man who is so inseparable from the great age of discovery and the English scientific establishment. As always, he comes across in this book as remarkably generous and egalitarian. I strongly recommend reading The Age of Wonder by Richard Holmes for more on this extraordinary man.

One final word, on this book. I really enjoyed the chapter where Winchester tells of his own experience as a child, walking from school down to the beach, where he discovered a fossil. (To his regret, he lost it at some point before adulthood, and was never successful at finding one as perfect as that one.) It is clear that Winchester still has that sense of wonder - and it really comes through in his writing.

Fortunately, Winchester has written quite a few books, so I expect I will be enjoying his writing for years to come.

***

A few fossils from our perambulations:

This is from Guadalupe Mountains National Park in Texas: it is part of the Permian reef which also contains Carlsbad Caverns.


Cenozoic era fossil at John Day Fossil Beds National Monument in Oregon. 

Saturday, September 23, 2017

Great Basin National Park

This post is part of my series on the National Park System. One of my goals while the kids are still at home is to visit as many of the National Parks and Monuments in the Western United States as we can.

Nevada is one of those states where everyone knows a city or two - and may well have been there - but the vast majority of the state remains unknown and unexplored. For Nevada, Las Vegas is the picture most of us have. Bright lights and golf courses in the middle of a searing desert, slot machines and half-naked chorus girls, Elvis and Liberace. Perhaps a vision of Reno, the scrawny little sister not quite as glam as the big sister. But these are just a very small slice of Nevada. Sure, the population mostly lives in these cities (¾ live in the metro Vegas area), but the great expanses of the state are usually not thought of at all.

This is a shame, as Nevada holds a lot of beauty and open spaces - and isn’t just hot desert either.

The name “Nevada” itself comes from the Spanish and means “snow-covered.” It isn’t really used in isolation, however: it is one half of “sierra nevada” - snow covered mountains. (The highest range in California is indeed the Sierra Nevada.) And the name makes sense. Nevada is the most mountainous state in the lower 48 by several measures. It has more named mountain ranges than any other, more peaks over 10,000 feet, and more than 30 over 11,000 feet.

Most of the state is in the “range and basin” part of the Great Basin Desert. This is a fascinating bit of geology. The Great Basin gets its name from the fact that within it, all rivers drain internally and never reach the ocean. The water all sinks into the ground or evaporates. The Great Basin extends beyond Nevada, of course. The most famous lake within it is the Great Salt Lake in Utah. The portion of California east of the Sierra Nevada - including Death Valley - is also mostly within the Great Basin.

“Range and Basin” is another matter. In the distant past, plate tectonics pushed up the Rocky Mountains. This compressive force raised much of the western North American plate to a fairly high altitude. Later, a shifting earth led to decompressive forces, and a large area spread apart. It didn’t just spread, however, it cracked into a series of blocks. Those blocks then tipped over. Imagine a stack of dominoes on its side in a box a bit too big for it. If they fall over, they will make a series of edges and valleys.

That’s basically what happened to make the Range and Basin formation. The result is pretty interesting to experience in person. Death Valley is the deepest of the valleys formed, but it is just one of dozens. The whole area consists of mountain ranges and valleys running north and south for hundreds of miles. Thus, if you want to go east to west (or vice versa), you go up and down and up and down over and over. But going north or south, you can settle into a fairly flat valley and drive perfectly straight for hours on end with beautiful mountains running on each side.

At the far eastern side of Nevada, about halfway up the state, there is a national park. Did you know that? Not too many do. Great Basin National Park is a fairly recent park - Congress elevated it to National Park status in 1986, during the Reagan administration. (You know, in those halcyon days when Republicans still believed in protecting wilderness rather than just despoiling it for profit…) Before that, it was known as the Lehman Caves National Monument - designated as such by president Warren Harding. (And that’s about the only good thing I have to say about Harding, who probably was the most corrupt president in American history. Although we may be about to set a new record.) The caves are indeed worth protecting, but there is more too.

Great Basin National Park contains Nevada’s highest mountain, Wheeler Peak, at 13,063 feet. Okay, so that is debatable. Boundary Peak is on the California-Nevada border, but it is considered a sub-peak of Montgomery Peak in California. Make of that what you will. Wheeler Peak is notable for being easy to summit - there is a trail all the way to the top, and you do not need rock climbing or mountaineering skills. I didn’t get a chance to hike it this visit, but I do wish to hike it next time. I have yet to summit anything over 13,000 feet, so this one is definitely on my list. 

 Wheeler Peak is the one to the right.

The peak itself is connected to one of the longer mountain ranges, but it stands far above the rest. From the east side (which is where the access is), it appears to rise out of nowhere in a flat valley. 

 Looking west from Baker, NV. Wheeler Peak is in the center background.

On the upper flank of the mountain, at near the 11,000 foot line, is one of two ancient Bristlecone Pine forests. The other is in the White Mountains (also Range and Basin) in eastern California. (I have visited there - I may have to write about it eventually.) The Bristlecone Pine is the oldest living non-clonal organism. Some of the trees here are nearly 5,000 years old. Bristlecones are really amazing to see in person. Because of their slow growth in inhospitable environments, they twist into fantastic and surreal shapes as they grow old. Most of the tree may die, while just a sliver of bark covers one side - and this sliver will continue to grow for thousands of years in some cases. Great Basin NP is a good place to see these trees. However, I prefer the California location both because it is closer to me and because there is a much larger and accessible grove so you can see more trees up close. But by all means go see the ones at Great Basin.
My boys with a Bristlecone about 3200 years old. The left side is still growing. 

 
This is the iconic tree that graces many postcards. It is dead now, but it has stood like this for over a thousand years. These trees do not decay quickly, and some of the wood here is over ten thousand years old. This is one of my favorite shots of all the ones I got.
 
Other things to see include a small glacier - we hiked most of the way before impending thunderstorms threatened. The mountain makes its own weather, so summer storms are a common occurrence. The forest is also lovely, with lots of Engelmann Spruce, which we don’t see much in California. 


 Small glacier at the head of the cirque.

 Engelmann Spruce cones.

 Clark's Nutcracker

 Wild turkeys

 One of my favorite pictures. 

 Some really big ears.

 A magical aspen forest

 Meadow, forest, cirque, and Wheeler Peak on the right.

 The best part of the park, however, is probably the cave. The Lehman Caves are located near the “base” of the mountain, at around 6,800 feet elevation. This statement should give an indication of how high the valleys are in Nevada. Anyway, the cave is pretty amazing. I love caves, and have been in quite a few, mostly in California, but also in Arizona, Tennessee, Texas, and Oregon. I think that of all the ones I have seen, Lehman is the best. It is pretty large, but the passages are narrow enough that most of the formations are close enough to see very well. And the formations! It’s not just that they are nice, but that there is such a wide variety. Pretty much anything you see in a cave is there, including rarer formations like “cave shields.” (Google the term, and Lehman Caves will come up…) I have been in caves with more of each formation. For most formations, I can think of specific examples in other caves that are fantastic. But I can’t really think of any other cave with all of them in the same place. 
 Cave formations
Cave Shield
 
Unfortunately, because we saw this park on our way to see the solar eclipse, we only had one day to explore it. I hiked about six miles in addition to the cave, but it would have been nice to have had time to explore more - and maybe even hike to the peak. The campgrounds seem rather nice, but you can’t reserve them, so it might be risky to drive up and hope. We reserved a site at a local RV park, which was okay as a base camp, but not spectacular as a campsite. When we return, I will probably camp some place on the way up, like Cathedral Gorge State Park, then get up early and try to grab a site on a weekday morning.

Also important for planning purposes: the nearest (and pretty much only) town is Baker, Nevada, which is extremely small. Count on bringing your food, as options are limited.  


Tuesday, July 11, 2017

Reading the Rocks by Marcia Bjornerud


Source of book: Borrowed from the library

This is an unusual book for the reason that I recommended it to someone else before I read it myself, which is not how I usually do things. However, that friend said she liked it, so I figured I would have to go read it.

Bjornerud is a professor of geology at Lawrence University, so she knows her stuff, but also has a rather poetic writing style. I was expecting a more systematic study of the subject, but won’t complain about the way she approached the topic, other than to say that the book makes more sense if you have at least had a grade school course on earth science.

A little background on this may be helpful. I was homeschooled from second grade onward, in an era when homeschooling went from fringe to mainstream. When I started, curriculum wasn’t easy to obtain - if I recall, even the mainstays of religious homeschooling curriculum now had to be purchased on the gray market. Now, of course, pretty much anything used in public or private schools can be readily found in homeschool-specific versions. And between the internet and the wonders of capitalism, there is so much out there, much of it free. (For example, Phil Plait’s wonderful Crash Course Astronomy videos.) But it was not always so. About all we had was A Beka and PBS.

So anyway, because of what was available and my family’s religious beliefs, the curriculum had a lot of gaps. While my dad wasn’t a young earther, that was (and is) the dominant belief in Evangelical circles, and A Beka definitely fell into that category. And not just by claiming evolution was an atheist conspiracy, but by ignoring or glossing over much of geology, because that led to some uncomfortable places for their theology.

I didn’t particularly suffer from this deficit, though, because I was (and am) a voracious reader, which my parents encouraged. I probably knew more about science in general than most kids my age, and our regular trips to geologically interesting places gave me field experience as well. To be clear, I got a solid academic education. However, I do know that many homeschooled kids do not get this kind of background, and at least in my experience, science and math tend to be weak points for many. (To be fair, science and math are weak subjects for Americans in general, compared to the rest of the first world.)

Despite the YEC propaganda in the culture I grew up in, I don’t think I ever bought into the idea of a young earth. The problem was, there was just too much overwhelming evidence all around. I live in California, which, like most of the western US, has a lot of exposed rocks. And it has earthquakes. And huge mountains. In fact, in geological terms, our mountains are fairly young, which means the way they were formed is rather apparent to the eye, if you know what to look for.

I have lived within about 50 miles of the San Andreas Fault for most of my life. And that fault has created features in the landscape which tell stories. There is Vasquez Rocks, famous for its use in film, which was a favorite destination when I was a kid. There, the layers of breccia and conglomerate are tilted and cracked from the pressures of the fault, and contain fossils from the past.

At various places along the fault, like at the Carrizo Plain National Monument, you can see where hills and creek beds and rock formations have become displaced by the movement of the fault.


Wallace Creek at Carrizo Plain NM in 2014. 
The kids are literally standing on the fault, which displaced the stream bed about 600 feet. 
Crazy dry that drought year - this year, everything was covered in flowers - so many you could literally see it from space.


Even driving interstate 5 north from Los Angeles, you can see where the hills on each side are quite different.

However, the two most interesting features have to be Pinnacles National Park and Point Reyes. In each case, entire rock formations are displaced by hundreds of miles. In the case of Pinnacles, the rest of the extinct volcano is located far south. In the case of Point Reyes, the whole peninsula was moved up the state over time, and it clearly was just stuck on the side there.

And then there are the other western places of geological interest: Zion, Bryce, the Grand Canyon, Lassen, and so many more. All these rocks tell stories of their origin, and those stories do not fit with a young earth. This much was obvious even to teenaged me.

Back to Reading the Rocks. The strong point of this book is in the explanations of how we read them. Contrary to the Evangelical conspiracy theories of my youth, geology isn’t just a made-up explanation to exclude the divine. Rather, there are known processes by which things happen. Plate tectonics are responsible for more than you would realize, radiometric dating does indeed indicate the dates on many rocks, and the fossil record does indeed tell of a history of life very different from our own age. As Hutton put it, “The ruins of an older world are visible in the present structure of our planet.”

Probably the chapter that had the most material that I didn’t already know was the one focusing on the role of water in geological processes, particularly subduction. Pretty fascinating stuff.

Also of particular interest was the chilling account of mass extinctions of the past (including a period when the earth got chilled.) It is frightening to me how cavalier many people are about climate, thinking that there is no risk. The underlying dynamics have been understood for hundreds of years, and we can see from the past that bad things can accelerate. But I guess that goes along with a general hostility toward science in this country, and a tendency to make everything into a partisan issue. (Yeah, I actually remember when Republicans were in favor of conservation and someone like Nixon could found the EPA without half the country thinking it was a Commie conspiracy…)

I also appreciated the way that the author worked in the history of how geological ideas and techniques were developed. It really helps to know how people reached conclusions, not just what they discovered.

Anyway, there is a lot to like in this book. Bjornerud writes well, and keeps the topic interesting and memorable. I will definitely continue to recommend this book.

Just one final thought to end it. Early in the book, the author notes that geology can be intimidating, because of the language, much of which originated before geologists had our modern understanding. Thus, the terms are often anachronistic and misleading.

But nomenclatures outlive the systems that spawned them, and over time the technical vocabulary of geology has become an idiosyncratic melange of anachronisms, synonyms, and some genuinely useful terms.

And, in a move that warms my heart, she then quotes from Mark Twain’s autobiography about the riverboat mate whose reading consisted solely of Lyell’s Geology.

All he wanted out of those great words was the energy they stirred up in his roustabouts. In times of emergency he would let fly a volcanic irruption of the old regular orthodox profanity mixed up with and seasoned all through with imposing geological terms, then formally charge his roustabouts with being Old Silurian Invertebrates out of the Incandescent Anisodactylous Post-Pliocene Period and damn the whole gang in a body to perdition.

Tuesday, May 16, 2017

Crater Lake National Park

This post is part of my series on the National Park System. One of my goals while the kids are still at home is to visit as many of the National Parks and Monuments in the Western United States as we can.

Crater Lake National Park is located in southern Oregon, in the Cascade Range. Believe it or not, I had never visited it until last summer. My grandparents lived for a few years in the Eugene area, and we used to drive up there. While we went up through the Redwoods one year, we never did manage to get to Crater Lake for some reason.

Crater Lake itself is a relatively new feature, geologically speaking. A volcano, Mount Mazama, blew its top off completely about 7,700 years ago. That’s during recorded history - a mere blink of an eye in geological time. In fact, the Native Americans in the area have stories about the eruption that go beyond the mythical origin story genre into details that indicate that there were eyewitnesses to the devastation.

This youth is in contrast to many of our favorite National Park and Monument destinations, which were formed millions - or even billions of years ago.

Anyway, the top of Mount Mazama blew off, transforming a typical cone shaped volcano into a caldera. The bottom fell in when the magma retreated, leaving a crater. And what a crater it is. The lake itself is 2000 feet deep. And the walls are literally nearly straight down. The walls then extend an additional 2000 feet up from there. Pictures cannot do this justice - it is an epic place and truly larger than life.

Crater lake has no outlet - and no inlet. All the water that comes in is from direct snow and rain. And there is a lot of it. As in 43 feet of snow in an average winter, plus a good bit of summer rain. All the water that leaves does so from evaporation and seepage. That mountain isn’t exactly watertight, so there are springs all around the outer slopes.

We took two hikes for lake views. The first was Mt. Garfield, which towers over the lake. This is a great hike in the moderate to difficult range, depending on your conditioning. It is worth the trouble for the spectacular views. The other is the hike down to the water’s edge. We did this after a storm blew in, so the lake itself was fogged in.

In addition to these, there are several other view trails, some of which were inaccessible because the south rim drive was closed. There are also a few short hikes on the outer rim, which are quite nice. (Although there were a lot of mosquitoes, something we Southern Californians are not used to.)

We camped inside the park - the campground is quite nice. There are other options, however, including the lodge right on the rim.


Pictures:



  Composite picture from the rim.


The kids and me on top of Garfield Peak. Yes, there was still snow there in July.


This is a good perspective on how steep the terrain is, and how clear the lake is.


Clark’s Nutcracker

The meadow by Annie Creek. This short loop is right by the campground.



Striped coralroot, a parasitic relative of the orchid. 
These are very ephemeral, so I was fortunate to catch one before it faded.


Golden Mantled Ground Squirrel 


Down by the shore on a rainy day.


Tuesday, December 1, 2015

Point Reyes National Seashore

This post is part of my ongoing series on the National Park System. The index is here.

One of the characteristics of living in California is the threat of earthquakes. I personally remember three as the most memorable. First was the 1987 Whittier quake, which was strong and close enough to where I lived in the San Fernando valley that it woke me up. Threw me out of bed, really. The second was the 1989 quake in the San Francisco area, which knocked a freeway down, among other things. That one was strong enough to feel all the way down in Los Angeles, believe it or not, and it wasn’t until the news came on that we realized it wasn’t just a common small quake in our area. The third was the 1994 Northridge quake, which killed quite a few, knocked down a key overpass leading to a traffic nightmare for months, and destroyed my uncle’s apartment. During my late teen years, we lived - literally - within spitting distance of the San Andreas Fault.

I mention all this as an introduction to Point Reyes National Seashore. This park is located about an hour north of San Francisco, on the other side of the Golden Gate Bridge.

Point Reyes, as a geological formation, is an interesting specimen. It consists of a top layer of conglomerate, with underlying granite. The specific rocks do not match anything else in the area. Even a brief look at a map shows that Point Reyes seems to be disconnected from the rest of the area. (This is even more apparent when one sees the ridge of hills 1500 feet high on the extreme eastern edge. It’s like someone made a giant knife cut across the boundary.)

(Official map from the NPS)

Those rocks, however, do match rocks elsewhere in California. Specifically, the granite matches rocks about 300 miles to the south, in the mountains north of Los Angeles, while the conglomerate matches rocks about 90 miles to the south near Carmel. Well, it turns out that there is a reason for this. Point Reyes is on the west side of the San Andreas, while the matching rocks are on the east side. Over the last 100 million years (more or less), Point Reyes has moved many miles north of its former location.

[For those interested, a more detailed geological history with some great pictures can be found here.]

In addition to the evidence from the rocks themselves, there is additional historical evidence of the move. During the famous 1906 San Francisco earthquake, the actual rupture occurred at Point Reyes, and left signs clearly visible at the surface. The displacement in this area was 16 feet, leaving fences disconnected. Crazy stuff.

We spent a day hiking and exploring at Point Reyes this fall. We were fortunate to enjoy a rare sunny day there, with neither fog nor rain to spoil the views. It wasn’t even particularly windy. There are a total of about 150 miles of trails, so we just scratched the surface, but what we did see was quite beautiful. Point Reyes is free to visit, which is unusual in the National Park system. We look forward to coming back and exploring more of this place.

 The view from Mt. Wittenberg

Hiking in the forest

 Fungi

Banana Slug. My kids were thrilled to finally see one.



You can tour the lighthouse, which has the original first order Fresnel lens intact.


Sunset over the point.