GENERAL GEOLOGY 



307 



a somewhat annular type of drainage aljout the tower, tlie presence 

 of agglomerate exposed at one place near its base, the compact character 

 of the rock composing the tower, and its association with undoubted 

 laccoliths in the same general region as some of tlie evidences in favor 

 of a laccolithic origin for tlie tower, but sa3fs (page 266) : 



"The most conclusive evidencesagainst a subjacent couduit to the Mato Tepee 

 mass are the presence of black shale in the agglomerate, the undisturbeu 

 horizontal beds which the tower rests upon, and the vertical columns." 



General Geology 



The sedimentary rocks of the region consist of yellow and gray Cre- 

 taceous sandstones and shales, generally with a gentle dip to the north- 

 ward in the Puerco Valley district. After the tilting of these beds the 



Cabe zon 



Cabezon f\ak 



FlciUUE 1. — Sketch Mail of the Mount Tdiilnr Ittijioii. 

 Black dots show location ol' some of the necUs. 



region was reduced by erosion to a surface of rather faint relief. This 

 peneplain neatly bevels across the inclined layers, as can be distinctly 



