146 CONSTRUCTION SOURCES OF GRAVEL, MINTZER 
positions within the moraine, unless these spots are results of feathering from the 
deeper deposits washed out of elevated or higher topographic positions. Accordingly, 
the area East of Van Buren would be expected to be generally granular. For the most 
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Fig. 1. The trend of lake beach ridge may be seen in the copy of 
a portion of the U.S.G.S. Topographie Map, Findlay Quadrangle. 
part, the composition material would be expected to be several gradations of sand, with 
a scarcity of very coarse materials. 
It was seen from the photo pattern that the structural situation underlying the 
area had very little influence upon the general topography of the area investigated. The 
underlying rocks in the study area were reported to be flat-lying limestones belonging 
to the Niagara and the Waterlime groups, the former underlying the latter. These 
limestones were reported to be of sufficient quality to be useful for construction purpo- 
ses, such as aggregate, foundations, flagging, and lime [11]. 
Mosaic and stereo photo study. 
Photographs of the terrain at about 1 :20,000 scale, were ordered for the study. 
After receiving the order a mosaic of the photos was assembled and stapled to celotex 
board. The different photo patterns observed on the mosaie soon became associated with