17MB PDF - Association for Mexican Cave Studies

174del Pa1mito, one of the larger and more impressive North Americancaves, is undergoing revision, and soon a revised plan and profileof this cavern will be available. This cave, about 65 miles northof Monterrey, is essentially two large rooms and reaches a depthof 667 feet. The map of the commercially developed Grutas de Villade Garcia near Monterrey has been completed. Recent work haslocated several caves encountered in the Go1ondrinas Mines, andseveral more caves have been visited in Huasteca and other canyonsjust west of Monterrey. The caves in the area north of Monterreyrepresent a variety of types. Gruta del Pa1mito and Garcia greatlypredate the existing topography and are deep phreatic caves developedin favorable reef areas probably during a more humid climateof the late Tertiary. Only a few remnants of the probably muchgreater number of shallow phreatic caves have been preserved inthis area of high relief and rapid erosion. Some of the cavessuch as Grutas de San Bartolo in C~6n de 1a Huasteca have a complexhistory of invasion and deposition of clastic fill.To the south between Monterrey and Cd. Victoria, Tamps. liethe limestone ranges of the Sierra Madre Oriental with peaks extendingto over 12,000 feet. Exploration of this rugged area hasonly begun. A few caves have been visited in the E1 Diente areajust south of Monterrey and some small caves have been examinedwest of Montemore1os and Hidalgo. The largest cave yet located inthe area is Cueva de La Boca, also called Gruta de Santiago, locatedjust southeast of Monterrey. This is another deep phreaticcavern, and is essentially one large passage in places over 400feet high. In this area south of Monterrey the limestone is ofvery great thickness and doubtlessly will contain additional largecaves, but the rugged terrain makes access difficult.South of Cd. Victoria the higher ranges receive larger amountsof rain and there has been considerable karst development. In theSierra de Guatemala southwest of Cd. Victoria a karst has developedcharacterized by numerous deep pits and almost impenetrable areasof vegetation-covered karst pinnacles. No large horizontal cavesystems have yet been found in this area but some will probably beencountered, both in the exploration of the deeper vertical systemsand in other parts of the range yet to be investigated. Thedeepest system explored in this area is the s6tano de 1a Joya deSalas, located about 45 miles southwest of Cd. Victoria, just westof the crest of the range. This pit is near the bottom of a largeclosed valley and receives much runoff after infrequent heavyrains. It has been explored to a depth of 896 feet and a recenttrip indicates that it might soon be possible to reach a greaterdepth. Exploration is now blocked by perched water that may beexpected to drain. In the same range in the vicinity of Ranchodel Cie10 northeast of G6mez Farias, 10 pits have been explored inan area of about 4 square miles, the deepest being 400 feet. Thisappears to be typical of the east face of the range. Several caveswest of G6mez Farias composed primarily of single, irregular roomshave been investigated. Evidence of extensive horizontal developmentat elevations near the present base level is the large horizontalpassage in Bee Cave located just above the present watertable at a relatively low elevation south of G6mez Farias, and thegenerally horizontal nature of the caves associated with the nacimientos(resurgences) of the Rio Frio and Rio Sabinas. The RioSabinas appears to floW from a large passage not far below thewater level, and Cueva del Nacimiento del Rio Frio contains a