Pleistocene Pocket Gophers From San Josecito Cave, Nuevo Leon, Mexico

/em> in the deposits strongly suggests a tropical situation in the vicinity of the cave when these gophers were taken, because the distribution of this genus today is entirely within the Tropical Life-zone.

Since the presumably early time when tropical conditions, or more nearly tropical conditions, prevailed at San Josecito Cave, climatic shifts account for a humid boreal environment there and its associated fauna. Findley (lit. cit.:635-636) reports from San Josecito the remains of the boreal shrew Sorex cinereus that today occurs no nearer than 800 miles to the northward in the mountains of north-central New Mexico. As he points out, that species requires hydric communities of cool climates, and in the Wisconsin Glacial age such climates probably prevailed in the high mountainous region where San Josecito is located. Since the time when a more mesic boreal environment occurred at San Josecito, climatic shifts have favored more xeric conditions as are found in the vicinity of the ca