17MB PDF - Association for Mexican Cave Studies

143another 15 miles before we turned left on a side road for a shortdistance and parked at the base of the mountains. A trail ledfrom a hand-dug well by which we had parked, up a steep northsouthtrending side canyon, and into the cave. We estimated thetrail to be one mile long and several hundred feet gain in elevation.Grutas de San Bartolo turned out to be two separate caves,both on the east side of the canyon and perhaps 200 feet above thebed of the arroyo. The southmost cave is reached first as onefollows the trail. From here a trail leads back north at a higherlevel to the northmost cave. (For a map of the north cave seepage 144.) Our findings in the two caves were of biological interest.In the southmost cave we collected several varieties ofspiders, a scorpion, and a large black beetle while in the othercave we found a bat, Mormoops mega~hY11a. For a description ofthe caves see AMCS Newsletter, v.r, no. 2, p. 21. The hike downthe arroyo was in the dark, and after loading our gear in thetruck, we headed straight out of the canyon. It was only 6 milesback to pavement. From the entrance of the canyon we drove throughSanta Catarina, then Monterrey, and south on the Inter-AmericanHighwa~. Just before Villa de Santiago (about 22 miles from Monterrey)a rough gravel road east was taken, past the La Boca Dam,to a campsite in the river valley on the other side.4 December On downstream from where we camped, on the southcanyon wall, is CUeva de La Boca. (See map on page 145.) As inGrutas de San Bartolo, we simply explored the cave and made insectcollections. (See AMCS Newsletter, v. II, no. 2, p. 22 fora description of Cueva de La Boca.) The collection includedbeetles, millipedes, and spiders. Of note was the new 110 foottower paralleling the old one, which gives access to phosphatemining operations in the upper levels of the cave. The tower ismade of steel and looks far superior to the Old, dilapidated, rotten,wooden one at its side. But looks are deceiving. As ischaracteristic with many Mexican mining structures, it was builtas cheaply as possible - the largest size angle iron used was only1/8 inch thick. For lateral support it used the old tower andvarious formations along the way. In the middle it was out ofvertical a11ignment by over 2 feet. To make climbing possiblesections of ladder were attached with bailing wire, and this samewire was also used towards the top of the tower when the angleiron supply became depleted. The climbing of this tower, and thesucceeding narrow wooden ladders that led up into the dome, reqUireda strong mind with an ability to think of other things.We estimated the dome to be at least 500 feet high, but we nevercould actually see the top, even with a powerful flashlight. Bythe middle of the afternoon we were out of the cave, back to thetruck, and heading for Austin.