Also located within the Ogallala [Formation] is a very important [aquifer]—a porous, water-bearing rock formation. This fine-to coarse-grained [sandstone] is very porous and permeable and is the most important single water-producing formation in the Panhandle-Plains area.
Fig. 17. The white surface in the right foreground consists of [caliche] ([p. 26]) in the Ogallala [Formation]. Coronado Lodge can be seen in the right background.
Opal and [chert] are locally abundant in the Ogallala conglomerates. The opal, which is found in small cavities in the [conglomerate] is not of the gem variety but it does fluoresce. [Minerals] that exhibit [fluorescence] emit visible colors when exposed to ultraviolet light. For this reason, the Ogallala opal is sought after by [rock] and mineral collectors. The chert, a flint-like variety of quartz, occurs as [nodules] in the conglomerate and in a well-developed layer near the base of the [formation]. Both of these [siliceous] ([silica]-bearing) rocks were apparently prized by the Indians, who used them to fashion knives, scrapers, projectile points, and other artifacts. The Indians also learned that flat slabs of [caliche] were ideal for lining fireplaces and to construct primitive rock shelters.
A number of [Pliocene] vertebrates have been found in the Palo Duro area. Known as the “Age of Mammals,” the Tertiary [Period] was characterized by mammals as diverse as were the reptiles of the [Mesozoic] [Era]. Among these unusual creatures were such now-extinct species as the saber-tooth cat and the elephant-like shovel-jawed mastodon ([fig. 18]). The remains of these as well as bones of giraffe-like camels, pony-sized horses, and sloths have been found in the vicinity of the canyon. The grassy plains of Pliocene time were also inhabited by large tortoises which reached lengths of up to 3 feet ([fig. 19]). Dioramas showing how these animals might have looked, as well as their actual remains, are on display in the Hall of Pre-History in the lower floor of the Panhandle-Plains Historical Museum in Canyon, 13 miles west of the park ([p. 35]).
Fig. 18. This life-size model of a shovel-jawed mastodon is typical of the now-extinct, elephant-like creatures that lived in this area during the [Pliocene] [Epoch]. (Photograph courtesy Panhandle-Plains Historical Museum.)
Fig. 19. The carapaces of giant tortoises as much as 3 feet long have been collected from [Pliocene] [rocks] in the Palo Duro area. (Photograph courtesy Panhandle-Plains Historical Museum.)