Hansen, James 1975 Journal Mexico trip: Cd. Valles → W of Xilitla 4 May 0800 hrs After preparing specimens and giving the vehicle and contents a major reorganization we left our campsite at the Hotel Valles and headed W on Mex 70 for the Sierra Madre Oriental and higher elevations. We made stops at two localities in tropical deciduous forest - thorn forest intergrade, one at El Venadito, San Luis Potosi; the other .9 mi. E Vicente Guerrero, both on Hwy 70 in San Luis Potosi. Both sites had an abundance of oaks and thorn scrub, rock outcrops and drainages. However, once again a lack of herp activity was evident as only Sceloporus viridis were taken, three at the former site (SA-2, AG-1) and one at the latter (SSS). Continuing over the crest of the Sierras we entered the Central Plateau. This area was even drier than E of the Sierras with thorn scrub and even more xeric desert vegetation prevalent. At a point 15.3 mi. E Rio Verde, San Luis Potosi, we stopped to get take a few pictures, and then decided to work a dry wash off to the side of the road for Cnemidophorus. After ~15 minutes nothing had been found so and Philip