2I4 INTRODUCTION. 
the beds of dry arroyos whose yearly freshets wash away all vegeta- 
tion. Following these washes progress is possible, but at best the 
approach is extremely difficult. 
The valley has a general trend to the southeast. Its level bed of 
lime rock, a recent formation, geologically speaking, is in places 
covered with a deep layer of Kankad (red earth) produced by erosion 
of the surface formations, and in other places is absolutely destitute 
of any soil save the thinnest layer of vegetable loam. Upon the sur- 
face everywhere is a sparse forest- growth of thorny trees and chaparral. 
Animmense terraced incline, partly natural and partly artificial, forms 
the northern approach to the group of ruins. Commencing with a 
series of ruined steps flanked by walled embankments, it extends 
upward at a moderate angle until at a distance of 187 feet from the 
base it reaches the foot of a second great terrace, upon which stands 
Edifice No. 1 and various less conspicuous structures. The accom- 
panying map, Pl. XXVI, shows the ground plans of these buildings 
and indicates the terracing ina sketchy way. Surrounding the central 
group are other ruins, some of which are included in the map, while 
still others lie beyond its borders and are shown in separate figures. 
Excavations were made at many points, walls were uncovered and 
traced, cisterns were cleaned out, graves were examined and many 
objects of art were procured. Pottery and flaked stone implements 
were plentiful, but polished implements and specimens of sculpture 
were exceedingly rare. 
