THICKNESS OF WEBEE CONGLOMERATE. 173 



the highly inclined beds of the ridge. It seems probable that they are 

 identical with the shales observed underlying the limestones in the expos- 

 ures north of Pinto Peak. On Carbon Ridge the beds exhibit much the 

 same sequence of sediments as are found in the Spring Hill region, 

 the limestones being more or less siliceous and carrying interbedded con- 

 glomerates. On the summit of the ridge there is a considerable develop- 

 ment of thinly bedded calcareous shales, in places fossiliferous. Unlike 

 this horizon at Spring Hill, abundant structural evidence exists here to 

 show that the uppermost members of the Lower Coal-measure series are rep- 

 resented, as the Weber conglomerates overlie them conformably. Between 

 the beds of the two epochs a peculiar structural feature may be noticed in 

 the narrow ravines which have been worn out by erosion along the contact 

 of the limestones and conglomerates. These ravines, which start in with 

 approximately north and south trends, invariably curve to the east and cross 

 the conglomerates at right angles to their strike, breaking up the formation 

 into individual blocks, which are united to the main body of Carbon Ridge 

 by low, connecting saddles of conglomerate. 



Everywhere the conglomerate is seen to overlie the limestone conform- 

 ably. Estimating from the observed dips and strikes, the Lower Coal- 

 measures of Carbon Ridge show a thickness of 3,500 feet, which does not 

 vary essentially from the development found on Spring Hill and is within 

 the measurement obtained for the horizon in the Diamond Range, where the 

 structural relationships with both the upper and lower beds are much better 

 determined. The Weber conglomerate has been regarded as dipping 

 uniformly, throughout the entire development, at 70, and upon this assump- 

 tion is assigned a thickness of 1,900 feet. This allows the conglomerate 

 100 feet less than the estimated thickness in the Diamond Range, but 

 here the uppermost beds are known to be buried beneath a greater 

 or less accumulation of tuffs and pumices. That there is about 

 the same thickness of beds and great similarity in the nature t.f 

 the sedimentation, is evident from a comparative study of the two 

 regions. No specially favorable locality for the collection of fossils was 

 recognized in the limestones, mainly because none were sought, but through- 

 out the entire series of beds Coal-measure forms may be found. Such 



