17MB PDF - Association for Mexican Cave Studies

178this area, but the uncovering and rejuvenation of the ancientkarst terrain is a process that warrants further study.In southern Veracruz near the town of Orizaba several largeresurgences have been investigated, the largest being Ojo de AguaGrande. South of Orizaba near the town of Tequila a small areahas been intensively investigated. The town lies in a deep narrowkarst valley. Several short streams flow from springs and sinkinto caves and pits along the valley floor. A large number ofpits has been located, the deepest being S6tano de El Crucero, 364feet deep. Sotano de Oztoatlicholoa reaches a depth of 700 feetin a series of drops. Both these caves have narrow stream passagesat the bottom. Well-developed karst forms a wide belt from nearOrizaba and continues southward through Tequila into the Huautlaarea in northern Oaxaca. Here there are karst highlands over onemile above the Rio Santo Domingo. In one place a slope descendsover 6000 feet into the river with an average angle of greaterthan 45 degrees. Little work has been done in these highlandsbut preliminary investigation has found two large caves just eastof Huautla where water from the western mountains flows into pitsat the edge of the limestone outcrop. The largest is the RioIglesia, flowing through a valley that ends against the west edgeof the outcrop. The river enters a large, unexplored cave system.Other similar caves exist in the vicinity, with S6tano de SanAgustin dropping 250 feet into a steeply sloping passage carryinglarge amounts of water. It is likely that investigation into thisarea will reveal large and deep cave systems.Several large karst areas are as yet unvisited by members ofthe AMCS, including the well-developed karst of Chiapas, Tabasco,and Yucatan. Yucatan has been covered by others, but both Chiapasand Tabasco have large areas of promising unexplored karst. Alongwith the geological investigation of the caves, a biological inve&­tigation is being conducted. James Reddell, presently at the Universit,yofKentucky, is coordinating this work. From collectionsobtained in several hundred Mexican caves, a picture of the distributionof cave-inhabiting animals is emerging. In this investigation,many new genera and species have been discovered, as well asnumerous range extensions. The wide range of climate and reliefpresent in Mexico make it possible to isolate the effect of thevarious factors that influence speleogenesis. Several slides willbe shown illustrating this variety of climate and terrain. Then,a tentative outline of the effect of these factors on speleogenesiswill be presented. (See next two pages.)