THE CENOZOIC GROUPS. 163 



River to be at the same horizon, namely, at the base of the series, and that 

 the attenuation is due to the non-deposition of the upper beds over the area 

 here brought to light, Of this, conclusive evidence was not obtained, and 

 it may possibly be that these conglomerates represent higher beds which, 

 farther from the shore, were sandstones of more thoroughly comminuted 

 material. But, while I suggest this possible explanation, I am inclined to 

 consider them as belonging to the lower members of the group, and that 

 after their deposition the area was left as dry land, while the sands were 

 accumulating in the bed of the lake farther from the axis of upheaval. 



From the Green River eastward, nearly to the foot of Richard's Peak, 

 the base of the group is composed of bad-land sandstones with more indu- 

 rated beds intercalated ; the latter are usually light gray, sometimes quite 

 white ; the former are exceedingly ferruginous and sometimes shaly; but 

 from the western base of Richard's Peak, nearly to the outcrop of the Red 

 Wall limestone, conglomerates are found, and here the whole thickness of 

 the group is much increased. It is interesting to notice that these con- 

 glomerates are found opposite the outcrop of the Red Creek Quartzite. 

 But the materials of which the conglomerates are composed seem not to 

 have been derived from the quartzite, if I may trust my notes : and I should 

 here state that the geographic relation between the quartzite and the con- 

 glomerate did not occur to me while in the field, and in my notes on the 

 conglomerate I have mentioned that its bowlders are sandstones and lime- 

 stones, and that some of the latter contain Jurassic fossils; but I have 

 recorded observations at only two points one at Richard's Peak, the other 

 at Bruce Mountain. With the facts now at my command I am inclined to 

 think that when this conglomerate was formed, erosion had not progressed 

 through the Carboniferous groups and Uinta Sandstone so as to reach the 

 quartzite on the upheaved side, but that the conglomerate is composed of 

 sandstones from the Cretaceous groups, and limestones and sandstones of 

 the Jura Trias, and possibly, to some extent, from Carboniferous beds. It 

 would seem that the appearance of the conglomerate here is to be explained 

 by geographic, rather than by geological, considerations that is, the line of 

 exposure of the base of the group in this region is near to the old shore 

 line ; for it is manifest that here was a headland projecting from the Uinta 



