While avid American travelers are familiar with many regions of our country, few have likely been to the Bootheel of New Mexico. Part of a mountainous swath between the Chihuahuan Desert, to the east, and the Sonoran Desert, to the west, this remote, southwest appendage of the State consists of three north-south trending mountain ranges, separated by valleys of desert grassland.
The easternmost of the three ranges consists of the Little and Big Hatchet Mountains; the latter forms the southern end of the range and contains the higher summits (including Big Hatchet Peak, 8356 feet). West of the Hatchets is the Playas Valley traversed by Highway 81; the valley floor has an elevation of 4200 feet. Running down the center of the Bootheel, on the west edge of the Playas Valley, are the Animas Mountains, representing the southernmost leg of the Continental Divide in the United States; Animas Peak, the summit of this range, has an elevation of 8565 feet. West of the Animas Mountains is Animas Valley, traversed by Route 338 and having a floor elevation of 5000 feet. On the west edge of this valley are the Peloncillo Mountains that run along the New Mexico-Arizona line; this range has relatively low relief, reaching a maximum elevation of 6928 feet at Gray Mountain. The Animas and Peloncillo Ranges continue into northern Mexico, eventually merging with the Sierra Madre Occidental.
All three of the New Mexico Bootheel ranges have complex geology, composed of both fault blocks and volcanic deposits. The fault blocks, produced by regional stretching of the crust, contain Precambrian, Paleozoic and Mesozoic strata; these blocks and the associated volcanism developed during the Oligocene and Miocene Periods (30-20 million years ago). The valleys, which warped downward as the mountains rose, held lakes during the cool, wet Pleistocene but are now crossed by seasonal streams, fed primarily by mountain springs and monsoon rains. The higher summits of the ranges (especially in the Animas and Big Hatchet Mountains) act as sky-islands, home to a surprising diversity of flora and fauna, including many Mexican bird species during the warmer months.
