To show the irregularity of the dip of these rocks, the ridges that give the most marked features to the picturesque scenery incline eighty to eighty-five degrees, and then immediately west are several low ridges dipping fifteen to twenty degrees.
There is a somewhat extensive cave in the north portion of the sandstone ridge that forms the entrance to the “Garden of the Gods.” It is caused by the washing away of a soft layer, . . . These vertical ridges of red sandstone rise above the surface about two hundred and fifty feet.
Annual Report for 1867, 1868, 1869, 1870 (Hayden 1873, 143–44)
Three Views of the Garden of the Gods
(Annual Report for 1874 Field Season [Hayden 1876], Plates VIII and IX and Figure 8)
The Garden of the Gods is today one of the most well known and well visited geologic sites in all of North America. The spectacular scenery attracts visitors and locals by the millions each year. But the Garden’s human history goes back many centuries—in fact there is artifact evidence of humans in the Garden from as far back as 3,300 years ago. Stone hearths and tools and the bones of a butchered bison from that period have been found by archaeologists in the Garden’s main section.
The first known Anglo to visit the Garden was a fur trapper named Wll. Ketner, who carved his name on the northern Gateway Rock in 1731 (this date is obviously suspect, but it is what is inscribed on the rock). Two later pioneers, Rufus Cable and Melancthon Beach, gave the Garden its name in 1859—nine years before Hayden ever laid eyes on the area. The fame of the Garden’s geologic landscape lured Hayden to the area on his first quick visits to the Front Range of Colorado, and he and his survey returned often. The central 480 acres of the Garden were owned by Charles Perkins (president of the Chicago, Burlington and Quincy Railroad) in the late nineteenth century. He died in 1907 with the wish that the land be given to the city of Colorado Springs as a park to be free and open to the public forever. Other land acquisitions by the city have added to the original 480 acres, and the park now contains a total of 1,367 acres.
One of Hayden’s inexplicable decisions, given the lore of the Garden, is his near lack of any detailed study of its geology. His survey did linger long enough in 1873 for the three drawings shown here to be sketched. Other illustrations of parts of the Garden are sprinkled throughout his Annual Reports, but he never actually studied the formations with any kind of rigor. These rocks are of the same sedimentary strata he describes along the Front Range from north of Fort Collins all the way to Pikes Peak. Yet here, where the rocks and geologic structure are the best exposed, he says little. Maybe he decided that the Garden was already well known enough that he needed to focus on other areas or that the rocks and their structures had already been described with sufficient detail elsewhere along the mountain front. Hayden did include a significant amount of description of many of the sedimentary rocks the Garden has in common with place farther north along the Front Range. This is especially true in his discussions of Bear Creek/Morrison, section 5, and St. Vrain/Lyons, section 6. The Annual Reports include lengthy sections on the Fountain, Lyons, and Morrison formations—although he did not name them as such.
To the modern reader, Hayden’s geologic terminology for rock description is arcane and awkward. He used terms such as “Silurian beds,” “Calciferous group,” “No.1 Cretaceous,” and “Red Triassic sandstones.” Although in most cases these names are geologically correct, they lack the precision, comparability, and even the panache of current geologic nomenclature. We are used to hearing names such as the Fountain formation, the upper Lyons formation, the Morrison formation, or the Niobrara group. Although Hayden was never a completely thorough or consistent fieldworker, the naming system he used was not totally his fault. The science of geology was very young in the 1870s.
Fewer than seventy years earlier, geology was just beginning to be systematized as a science by British investigators James Hutton, Charles Lyell, John Playfair, William Smith, and others. It was not until the 1930s in the United States that there was any attempt to make geologic nomenclature consistent and precise. In 1933 a committee was formed to create guidelines for geologic naming. The result was the “Classification and Nomenclature of Rock Units” published in the Bulletin of the Geological Society of America (Ashley et al. 1933). A more permanent group with members from most of the subfields of geology met in 1946 to formalize the American Commission on Stratigraphic Nomenclature (now called the North American Commission on Stratigraphic Nomenclature). Very strict rules about naming and systematizing the geologic formation names are now in place. These guidelines and rules would have helped Hayden immensely.
The Garden of the Gods is the most spectacular geologic site along the Front Range, and it is a good example of the geologic forces and history of the entire foothills zone at the base of the mountain front. Its geologic history is long and complex, and it is always entwined with the various mountain-building episodes in Colorado and the West. As mentioned in the introduction, there have been several mountain-building episodes along the current Front Range of Colorado. The first that we can hypothesize about was 1.8 billion years ago. We postulate this from the remnants of the Idaho Springs metamorphic rock throughout the Front Range. The second was probably during the emplacement of the Silver Plume granite in the northern part of the Front Range. After these two orogenies, there was a massive intrusion of the Pikes Peak granite (1.1 billion years ago)—the largest batholith in Colorado and one of the largest in North America. Recent analysis of this formation has concluded that there was not an orogeny linked to this intrusion. The granite from this episode was not exposed at the surface—it solidified many thousands of feet below ground level. Some 700 million years later, around 300 million years ago, the third uplift occurred. The result of this third uplift is called the Ancestral Rockies. These Rockies eroded rapidly (in geologic terms), and most of the debris from these mountains was deposited along the base of the mountains to the east and some to the west. Because of the rapidness of the erosion and deposition, very little sorting took place and the rock produced is called a conglomerate—all various size particles, from clay to boulders, were molded together in one unsorted mass. This conglomerate is what we now call the Fountain formation, and Hayden called the “lower beds of the Red group.”
Between 300 million years ago and about 65 to 70 million years ago, the region we call Colorado underwent many transformations of elevation, environment, and geologic process. At times the area was very dry and spawned windblown sand dunes. At other times it was underwater and produced limestones, shales, gypsum, and claystones. At still other times there were extensive beaches and deltas. All were at relatively low elevations, sometimes all the way down to sea level and below. At about 65 million years ago, another orogeny began (locally known as the Laramide orogeny). The energy and force required for this uplift came from as far away as the current coast of California. Huge tectonic plates moving slowly but inexorably under the Pacific Ocean forced the uplift of the subterranean Pikes Peak granite. The exact tectonic mechanisms for this are still debated in geologic circles. As the buried granite was forced upward, it lifted and bent the formerly flat, overlying sediments. Some rocks were forced into a near vertical position while others now sit at around 35 degrees (variation that Hayden’s quote earlier in the section describes). The difference between the two angles of rock is caused by a large fault system called the Rampart Fault that runs through the center of the park. Some of the sedimentary rocks that were pushed up were not very resistant to erosion and now underlie the valleys in the park. Some were much more resistant, and these are the tall ridges of the lower member of the Lyons sandstone and the Fountain formation.
Although this is the simplified story of a complex set of geologic processes, the result of this geologic action can be seen in today’s Garden of the Gods. Most of the western side of the Garden is Fountain formation. Balanced Rock and Steamboat Rock, for example are Fountain as are the Cathedral Spires, also called the “Montezuma Temple Ruins” (see sketch and photo). The dramatic Gateway Rocks (rendered by Thomas Moran with Pikes Peak in the background) and the Tower of Babel (called “Cathedral Rock” by Hayden’s artist) are composed of Lyons sandstone—called the “Red Triassic sandstone” by Hayden. The Lyons formation is now placed in the mid-Permian time period.
The rocks themselves have changed little since Hayden saw them. There are some remnants of rock-climbing gear on the main formations, and the cave mentioned by Hayden has been closed off to the public, but the geologic character is still preserved. The land that winds among the rock formations, however, has changed significantly in 125 years. Extensive and intensive erosion caused mostly by hikers and horses is evident throughout the park. Attempts to ameliorate the erosion are becoming more and more evident—an example is the reddish concrete path you can see in the photo of Cathedral Spires. Substantial plantings of vegetation that were not naturally in the park also are abundant—Rocky Mountain juniper and white fir being the most obvious. These plantings were done early in the park’s history because people thought of the central part of the park as a kind of community garden and treated it as one. More insidious and often unrecognized vegetation problems exist also. The most serious is the invasion by nonnative plants that are able to outcompete the natives. The most egregious of these are several species of weeds and the New Mexican locust (Robina neo-mexicana), a tree that is extensive along the park’s eastern boundary. Efforts are being made to help eradicate these invasive species, but the plants are tenacious and difficult to remove.
The Garden of the Gods is a natural treasure for Colorado in general and Colorado Springs in particular. Time, effort, and money invested in the park are needed to keep it the “star” that it is. Hayden would still recognize the geologic story of the Garden; he would have a more difficult time recognizing the human-caused changes that have occurred in the park and in the city surrounding it.