The Western San Juan Mountains: Their Geology, Ecology, and Human History

19. Points of Interest Along the San Juan Skyway

CHAPTER 19 POINTS OF INTEREST ALONG THE SAN JUAN SKYWAY ROB BLAIR This road guide is meant for the visitor who wishes to delve into the geology, ecology, archaeology, and history ofthe San Jnan Skyway region. The guide is designed to be flexible so that a traveler can enter the highway at any point and circle the loop in either direction . The points of interest are identified on topographic maps (Fig. 19.1, Maps 19.1 through 19.20, and Maps 21.1 through 21.3) by open circles, with corresponding numbers referenced in this chapter. Areas of interest are designated with black-filled circles . Many ofthe points ofinterest are referenced to the green milepost (mp) signs found along the side of the road. Each winter, unfortunately, snowplows destroy some signs, and after major road construction the new signs may not measure true miles. The information for this road guide was obtained from numerous sources, including a number of previously published geologic road logs. These and other references are included at the end ofeach area ofinterest (dark-filled circles on maps). The flora and fauna information was provided by Preston Somers of the Biology Department at Fort Lewis College. Unless otherwise stated, all photographs were taken by the author. No guide of this sort can be exempt from errors; please bring to our attention oversights and misinformation. 1. (Map 19.1) Durango. Elevation: 6,512 feet (1,985 m). Population : 12,430 (circa 1990). Durango! Even the name conjures 249 250 The Western San Juan Mountains up an image ofthe Old West. Although lacking cowboys on saddled horses, the town still retains much of its original flavor through its friendly people and architectural style. The Durango & Silverton Narrow Gauge Railroad, Purgatoty ski area, and Mesa Verde National Park make this community one of the most popular tourist centers in the Southwest. Basketmakers II and III occupied the region thousands of years ago. These people were followed by the Anasazi and eventually by the Mountain Utes. Spanish explorers Juan Maria de Rivera in 1765 and Escalante and Dominguez in 1776 passed just a few miles south of the future townsite as they explored the fringes of the San Juan Mountains. With the arrival of white settlers in the 1870s, the first towusite in the San Juans, called Animas City, was established; in less than a decade, it became a thriving agricultural community. However, because the town was not willing to meet the demands ofthe Denver & Rio Grande Railroad in 1879-1880, a new town was created 2 miles (3.2 km) south. The territorial governor, Alexander Hunt, named the new community Durango after a town in Mexico. With the establishment of the narrowgauge railroad, Durango became a boomtown supporting local mining for coal, gold, and silver. Animas City was eventually annexed by Durango in 1947. Before European settlers entered the valley in 1870 and began planting and cultivating trees, the site of Durango was much more open (figs. 19.2A and 19.2B). A shrubland ofbig sage dominated the area, with a scattering of pinons, junipers, and ponderosa pines. All of the elms, maples, ashes, willows, Russian olives, and fruit trees seen today are exotic to the Durango area. The cottonwoods , blue spruces, white firs, box elders, quaking aspen, and chokecherries are native. The dense and diverse growth of both native and ornamental species in town today is appropriate for a well-watered river valley, but it exceeds any plant community nature would produce by itselfin this semiarid environment. The average annual precipitation in the Durango area is 18.6 inches (47.2 em), including the average snowfall of69 inches (175 em). Forty-two percent of the precipitation falls from August through October. ."-"'- N ~-"'- ~-." • ,. I • ,~ ~19,1 252 The Western San Juan Mountains Durango is built on Animas River gravels, which rest upon late Cretaceous sedimentary rocks, principally the Mancos Shale. Pcrins Peak (west) and Raider Ridge (east) are capped by the Point Lookout Sandstone. Animas City Mountain (north) is capped by the Dakota Sandstone and forms a conspicuous sloping surface dipping to the southwest at about 7 degrees. All formations in the Durango area dip south, toward the center of the San Juan Basin, a structural basin with a sedimentary thickness of nearly 12,000 feet (3,700 m). Just south of town the formations steepen to 35 degrees and form prominent hogbacks that represent the Hogback Monocline and...