Show notes
2026 marks 100 years of National Park Service Interpretation at Grand Canyon National Park. In honor of this anniversary, here's Louis Schellbach's introductory geology talk. Throughout his talk, he references geologic details once viewed through a series of mounted binoculars on the parapet at Yavapai Observation Station (now Yavapai Geology Museum). Schellbach served as the park's Chief Naturalist from 1941–1957. ---TRANSCRIPT:--- 00;00;02;27 - 00;00;25;14 Now, I might begin by telling you that we believe you came to enjoy yourselves and not to be educated. But we do believe that if you know what you are looking at, you will enjoy yourself just that much more. So this station then, is a government operated station built by the National Park Service primarily for your benefit. 00;00;25;16 - 00;00;48;05 Now, you come to Grand Canyon. You do not have much time. You do, of course, appreciate its rock sculpture and its color out there, but really, there is a lot more behind that canyon than just its rock sculpture and its color. So this station then has been built as a mechanism for you to use to interpret what you see out there. 00;00;48;08 - 00;01;18;23 Now, on the parapet here is this battery of high powered binoculars. Now, each and every one is fixed and fastened upon a particular spot in the canyon that has a story to tell. You cannot move these telescopes. And then beneath each telescope is a small exhibit box in which there are specimens that have been brought up from the spot on which the telescope is focused, so that you can see them close at hand. 00;01;18;25 - 00;01;47;20 In other words, saving you the time of walking down there. However, should you doubt any of the specimens in the cases here or inside, I'll tell you. You can reach any of those spots by trail, down below, and see the story in the rocks yourselves. However though, we fellows will tell you that the Bright Angel Trail from the rim to the river is only seven miles long. 00;01;47;23 - 00;02;17;12 To be accurate seven and 8/10 miles. Yet in the same breath, we will warn you that should you go down there, under your own power, turn about and climb out. Oh, you will swear it's 77 miles back. (laughter) You try it sometime. Now, you do not look through these telescopes with the thought of getting a wonderful view. No, they are not there for that purpose. 00;02;17;14 - 00;02;23;05 They are there to act as pointers, to point out the spot in the canyon. 00;02;23;07 - 00;02;47;29 Now, the object is to look at that spot through the telescope. See the place in nature. See its relation to the rest of the formations. Then look at the specimens in the box. Read the labels. Put two and two together as you go along this parapet. And by the time you've reached number 15 Telescope, you should have a good comprehensive idea of what that canyon stands for. 00;02;48;01 - 00;03;18;10 For they are the facts. You hook the facts together. Now, I took over 75 years of scientific research to wrest these stories from the rocks of Grand Canyon. Place it up there in that manner, so that you can get it in 20 minutes. If you will think on what you see. In other words, we want you to have the joy of discovering for yourselves. 00;03;18;12 - 00;03;42;27 We point out the fact, you reason on it. However, though once a day this time of the year, the man on duty here has to hook up these telescopes for you, to give you a Grand Canyon story. And today, of course, that duty happens to be mine, as well as my pleasure. But I always maintain that despite the long years of experience. 00;03;42;27 - 00;04;06;16 And I've been here over 22 years, and I happen to be park naturalist too, that despite those long years of experience, for me to give you a Grand Canyon story in the short time and allotted, seems a tremendous task. Oh, it's a terrific story, to try to compress it, into the short time they expect us to give it. 00;04;06;18 - 00;04;39;11 We have, however, broken it down into four main phases, so that we might present it easily, and so that you might grasp it easily. Now, the first phase answers your question; what happened? Did the earth crack open? Did glaciers cut it? What made that terrific gorge out there? The second great phase is Earth's history and Earth's building, as exposed to view in those canyon walls. 00;04;39;13 - 00;05;06;08 The third great phase is the record of life, through the ages, as found in the form of fossils in the canyon formations. And the fourth great phase is the canyon today, now, as it influences living things. Now you people keep those four main phases in mind as we progress, see? Number one, then, what made it? Number one telescope 00;05;06;08 - 00;05;36;03 there points to the river three miles away from you in an airline. And of course, you are not a bit impressed with the river. No, I don't blame you. It looks like a muddy, insignificant little creek down there, doesn't it? But, oh, how you are fooled. You're seeing that river three miles away. And at that particular spot, the river is over 300 ft wide. 00;05;36;06 - 00;06;01;26 And you know how long a city block is. And it's low water now, too. By the way; she will cover those white banks down there when the floods come down. And that little creek down there happens to be one of the world's most dangerous rivers. Now, no fooling. You see, other rivers have been servants to man. Highways of commerce, trade, communication. 00;06;01;28 - 00;06;31;08 But not to the Colorado River. Now, what happens to be the second longest river in the United States? It is over 2000 miles in length. And that little creek down there has one dangerous rapid for every day in the year. Now, that's 365 cataloged dangerous rapids. Oh, she has a lot more than that. But those are the dangerous ones. 00;06;31;10 - 00;06;59;17 And that little creek down there cuts 26 distinct canyons. 26 of them. 19 of which are major canyons. While Grand Canyon out here, of course, is the largest and the most spectacular of them all. The final major canyon it passes through on its way to the Gulf of California is Black Canyon. And in Black Canyon today is located Hoover Dam. 00;06;59;20 - 00;07;31;09 And from up here, three miles away, you can see the river is muddy. Oh, it's very, very muddy. So muddy, in fact, that we fellows say, "it's too thick to drink and too thin to plow." And that's literally true. For listen, by any point in this canyon, and this canyon is 217 miles long, one canyon, by any point in it 00;07;31;11 - 00;07;56;24 that river is carrying an average of a half a million tons of earth every 24 hours. Now, can you people grasp a half a million tons? Think of it in terms of five ton trucks, and you might get an idea of how muddy that river is. Now that, of course, happens to be just the average flow. Well, she carries much more than that in times of flood. 00;07;56;26 - 00;08;32;13 The record was September 13th, 1927, when one flood came through that canyon, and when that river carried 27,600,000 tons. By any point in the canyon, in 24 hours time. Now that's more than a million tons an hour. Literally moving land. You see, that river is growing through this canyon at a speed of from two and a half to 12 miles an hour, depending on the flood waters. 00;08;32;16 - 00;08;59;03 It has a drop of nine feet to the mile, and this canyon is 217 miles long. And because of that speed, the river cannot drop that load in this canyon. Oh, it must carry it outward. And only, of course when the river reached sea level at the Gulf of California, there the river slowed up, and there it was able to drop its burden, 00;08;59;05 - 00;09;34;23 and there it dropped It. There it built its delta many, many miles an extent and many thousands of feet deep. There that river, by the way, was building rock formations for the future, just as some of the rock formations out there, in the canyon walls, was built in the past by ancient muddy rivers. Now, I've just given you the explanation of the river because in my estimation, that is vitally, vitally important. 00;09;34;25 - 00;10;04;11 Oh, you must know something about that river, because that river cut this canyon. Now, how might I explain it to you briefly, un-technically and without hair splitting? Oh, I might attempt it in this manner. There are five great eras in Earth's history. Only five. No need for me becoming scientific, is there? And telling you they are 00;10;04;12 - 00;10;36;00 the Archaeozoic, Proterozoic, Paleozoic. Mesozoic and Cenozoic, see? Those are just scientific names. Now you people think of them as five chapters in Earth's history. In other words, the history of the Earth written in five chapters. We are living in the fifth chapter. It is the present, still going on. Now visualize this; sometime after the close of the fourth chapter, the Mesozoic, 00;10;36;03 - 00;11;08;07 the land in this entire region out here, was comparatively low above sea level, not as high as it is now. And through that low land there meandered a lazy, slow, sluggish, dying, moving river on its way to the sea. Now that was the Colorado River, and geologists tell us this is a young canyon out here, a young canyon just several million years old. 00;11;08;10 - 00;11;43;20 Oh, that's young, before I'm through, you'll be surprised. And then the land in this region slowly started to rise to dome-up, oh, so slowly. You just couldn't measure it. Any human being's lifetime. In fact, it may still be rising right here. But we don't live long enough to measure that rise and that slow rising of the land enabled the river to maintain its original course. 00;11;43;22 - 00;12;07;27 You see, if the land would have come up quickly, it would have blocked that river out there, and the river would have had to flow around the base of this gigantic dome, which is Grand Canyon, or it will look flat to you out there, I know. But it isn't. You must come uphill from, no matter what direction, to come to Grand Canyon. 00;12;07;29 - 00;12;45;18 Well, now the river and the canyon is not doing that. Cutting and flowing around the base of the dome. It is part way up and around the dome, proving the slow rising of the land. And as the land came upward, it did something else, it gave speed to that lazy river. And speed, of course spells power. Now, the material that that river was given to carry in the form of sand, silt, gravel, boulders, they became the tools that that power used. 00;12;45;20 - 00;13;16;23 And as the land came upward, the river ground and pounded and abraded and scoured and cut down through it faster, as it hit the softer layers of rock; slower as it hit the harder, until out there today, she is a mile below the rims. But don't lose sight of the fact I told you this started after the close of the fourth chapter of earth's history. 00;13;16;25 - 00;13;49;02 You now are working on the completion of the third chapter. The fourth was once above our heads. Here almost again as high as that canyon is deep. Hence that river has cut through almost two miles of Earth's crust, exposing to view, all of Earth's history in this region. For the river down below there, is cutting through ancient black rocks. 00;13;49;05 - 00;14;12;24 All the oldest rocks known to man. Wherever they are found on the face of the earth, they are number one. Number one in the scheme of things out there, no rocks any older beneath those rocks, in the bottom of this canyon where they go down, down to the magma layer, the molten rock layer upon which the Earth's crust rests. 00;14;12;26 - 00;14;40;08 So you see, then, as you people stand here and look out with just a little bit of inspiration, you suddenly begin to realize that you are doing more, oh, much more than just looking. You're looking back through the ages. Now that's how the river cut the canyon. But at no time was that river as wide as from this rim to that north rim over there, ten miles away. 00;14;40;10 - 00;15;10;17 No, the river probably was not much wider than it is today. It cut a narrow and straight canyon downward. But other forces are at work, eating away the canyon walls on the sides. Gravitation pulls down the loose particles, the trees growing along the edges of the cliffs, out here, their roots get into cracks of rocks, pry off pieces down they fall. Water getting into the cracks of rock in the wintertime and freezing. 00;15;10;20 - 00;15;39;06 Now, you people know what freezing water will do. Cliffs snap off and down they fall. Now eventually they get into the river in one form or another. And that river flowing so fast through this canyon cannot drop that load here. Oh, one 20 minute rainfall in this region will remove more land than an entire season's rainfall in a more vegetated region. 00;15;39;08 - 00;16;11;17 You notice out there afterwards the plants do not grow close together. Land wears away very, very rapidly here. That's what is widening Grand Canyon. And number two telescope. They're pointing to bent and twisted rock. Proof of land movements. Mother nature, in the beginning, puts the rock layers down horizontal: sea bottoms, lake bottoms, river deltas. Windblown sands. Stress and strains in the Earth's crust. 00;16;11;18 - 00;16;38;09 break them. Slipped them by each other. See that point over there? Hopi Point is 180 ft higher than this point, where the Earth's crust snapped and slipped 180 ft, right straight across Grand Canyon, making that side canyon over there. Oh, notice that white band or cliff below the rim opposite you over there. Now keep your eyes on that white band. 00;16;38;11 - 00;17;01;07 Now follow it to your right. Way at the head of that side canyon over there, where the rim is higher on the left then on the right. Right opposite you, drop below the rim to the white band, right where the snow is. Notice the white bands that way, instead of being that way, it's that way. Making the famous Bright Angel Fault. 00;17;01;09 - 00;17;32;07 Or these movements will bend the rock layers or it will over thrust them, or it will break the Earth's crust into blobs, and it will tilt the blacks up into mountain ranges. So when you see rock layers tilted or bent, you know there's been crustal movement at that place. However, though, to you know, since I've been on the job here, I found that that's mighty hard for most people to believe that land moves. 00;17;32;09 - 00;18;04;03 The Spaniard, you know, called it Terra Firma Farm land. You and I think of everlasting rocks and everlasting mountains. And there is no such thing as mountain ranges where a way to complete level plains, rocks disintegrate into sands and silts and gravels and mud are redeposited recently defied re thrust up into mountain ranges again to be again re worn down. 00;18;04;05 - 00;18;32;08 And as I always say in my later moments, the land she do move, she do that just because we don't see it move in our own lifetime. We don't believe it moves, you see. But if you live in an earthquake country, you know she moves up. Nobody in California today. 00;18;32;10 - 00;18;46;15 Actually get a rise out of people from California, especially the fellows from Berkeley in they say, oh, California. We don't call them right quakes. We call them adjustments there. And. 00;18;46;18 - 00;18;57;18 I have to make people laugh just a little bit. You ought to be up here looking at yourself. See this little. 00;18;57;20 - 00;19;24;07 Do you ever stop to think we're the only animals that can laugh? Let us know what we're laughing about, Sure. You might as well take advantage of it and prove right. Here we are, 7073ft above sea level, right here. We are literally on the top of a mountain. Yet this afternoon, if you people will look careful…
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