[Illustration: Fig. 23. Located on the canyon floor, Pioneer Amphitheatre is a modern outdoor theatre where symphonic dramas are presented each summer. (Courtesy Mrs. Ples Harper, Texas Panhandle Heritage Foundation, Inc.; photograph by Ron Horn.)] The lower one-third of the peak consists of deeply furrowed, red and white banded shales of the Quartermaster Formation (p. 17). Overlying the Permian red beds are the brightly colored, multi-hued Tecovas shales of Triassic age (p. 19). The composition of the Tecovas is such that the lower shales tend to weather into relatively gentle slopes with rather smooth surfaces. Triassic Peak is capped by a weather-resistant layer of Trujillo sandstone, and this durable cliff-forming sandstone has served as a protective covering to impede the erosion of the softer rocks of the Tecovas and Quartermaster Formations. Although it has withstood the ravages of time exceedingly well, the large blocks of Trujillo sandstone which litter the flanks and foot of Triassic Peak clearly indicate that weathering and mass-wasting have exacted their toll in the geologic past. [Illustration: Fig. 24. A trip on the Sad Monkey Railroad is a good place to learn more about the canyon’s geology and get a closer look at the rocks.] [Illustration: Fig. 25. Excellent exposures of the Quartermaster Formation of Permian age (1) and the Triassic Tecovas (2) and Trujillo (3) Formations can be seen in the south face of Triassic Peak. The feature known as the Sad Monkey is indicated by the arrow.] Sad Monkey, Texas derives its name from the prominent mass of Trujillo sandstone at the southern extremity of Triassic Peak. When viewed in the proper perspective—and with the proper amount of imagination—this massive block of sandstone bears a striking resemblance to an aged and saddened monkey. _Spanish Skirts_ (6).— Few of the canyon’s features are as well-named as the gaudy Spanish Skirts (fig. 26). The lower part of this multi-colored bluff consists of alternating layers of red and white Quartermaster shale, capped by the colorful maroon and lavender Tecovas shales. Located on the north flank of Timber Mesa, the Spanish Skirts and nearby Catarina Cave can be reached by an easy half-mile path. The trail begins on the west side of Park Road 5, just beyond the Timber Creek bridge located several hundred feet from the Sad Monkey Station. _Catarina Cave_ (7).— A short distance west of the Spanish Skirts lies Catarina Cave. This depression has been washed out of the relatively soluble Permian shales (fig. 27). _Santana’s Face_ (8).— Like Triassic Peak, Timber Mesa is capped by a thick layer of massively bedded Trujillo sandstone. On the eastern tip of the mesa the sandstone has been eroded in such a fashion that it resembles the profile of an Indian (fig. 28). This feature, called Santana’s Face, is best seen from the park road shortly after leaving Sad Monkey Station.