ABSTRACTS AND DISCUSSIONS OF PAPERS 121 



diameter of the larger boulders measuring 10 inches. Embedded near the base 

 of this conglomerate were found a series of sandstone blocks, the largest of 

 which measured 3 feet S inches by 7 feet 6 inches in its longest and shortest 

 diameters. Thirty of these blocks were counted in 200 feet of outcrop. The 

 material of which these blocks are composed consists of a fine-grained, evenly 

 bedded, friable, red sandstone. These blocks are very angular in outline and 

 the bedding planes of the various blocks are tipped at all angles. They present 

 a strong contrast to the well rounded, smooth, hard pebbles and boulders with 

 which they are embedded. It is evident from the size and angular outline, 

 together with the friable nature of the sandstone, that these blocks have not 

 been carried laterally any great distance, unless they can be conceived to have 

 been floated or rafted by ice action. A careful search was made for some 

 evidence of ice activities in the conglomerate, but none was found. In seeking 

 for an interpretation which will account for the presence of these blocks in 

 such a position, we have only to turn to some interesting facts recorded higher 

 in the same section. It might be well to note that the lower 500 feet of the 

 section, in which these blocks occur, is composed of heavy beds of a coarse 

 sandy to conglomeratic arkose, interbedded with a number of thinner bands 

 of fine-grained red sandstone, the materials of which are indistinguishable 

 from those comprising the above-mentioned blocks. At a height of 330 feet 

 from the base of the section one of these sandstone members was found to 

 have a uniform thickness of 7 feet. Some 18 feet above this member (348 feet 

 from the base) a second sandstone member, having a maximum thickness of 

 10 feet, was found to be channeled to a depth of 5 feet. At a distance of 370 

 feet from the base two large sandstone blocks, having regular bases on the 

 same horizontal plane, were found to be completely inclosed by coarse arkose. 

 The largest of these two blocks measured 26 feet long and 4 feet thick. Lastly, 

 at a height of 416 feet from the base four sandstone blocks, all with regular 

 bases in the same horizontal plane, were found completely inclosed by coarse 

 arkose. The largest of this set measured 2 feet 6 inches in thickness, while 

 the distance between the extreme ends of the two outer blocks was 50 feet. 

 In all cases these sandstone members were found to have irregular upper sur- 

 faces, while their lower were approximately straight, and in each set on the 

 same horizontal plane. From the foregoing it is apparent that we are dealing 

 in each case with what was originally a continuous sandstone member, which, 

 with the exception of the case noted at a height of 330 feet, has been channeled 

 previous to the deposition of the overlying arkose members. In the cases 

 noted from 370 and 416 feet from the base this channeling has cut completely 

 through the beds, thus permitting the overlying and underlying arkose mem- 

 bers to come together. We may carry this development a step further and 

 assume that during a period of exceptional torrential activity, when coarse 

 conglomerates were being deposited, such sandstone remnants of preexisting 

 beds may have been undermined by the lateral cutting of a stream and tum- 

 bled into the river bed, where they would be deposited along with the pebbles 

 and boulders being swept down by the torrent. This occurrence will be de- 

 scribed more fully in a subsequent paper. 



As to the stratigraphical relationships and age of this red-bod series, two 

 points brought out by this research might be mentioned. First, that all of the 

 limestone members (some ten having been recognized), which tend to repk -e 



