CLINTON CONGLOMERATES AND WAVE MARKS. 197 
If the elevation of land had been at all considerable, river 
valleys should sooner or later have been formed of sufficient 
depth to insure their preservation under the accumulating débris 
as the land gradually sank under the sea. The upper banks of 
these rivers would in this process form shores of the sea or inlets, 
with however a possibility of being less subjected to the brunt of 
the waves, and hence a better chance for preservation than more 
exposed shores. 
Nothing of the kind has so far been found in the area here 
studied. Conglomerates have been found, but the age of the 
pebbles forming the same is rather in favor of but low elevation, 
so low that even in the Clinton, with its small thickness of thirty- 
five feet, and its pebbles at times only fifteen to twenty feet above 
the bottom, no pebbles of Lower Silurian origin have been found. 
The pebbles, on the contrary, are now found only a very short 
distance above the horizons to which they originally belonged. 
This certainly suggests but a low elevation of these Silurian land 
areas, at least where so far examined. 
The point of greatest interest in all these facts lies, therefore, 
in the evidence of conglomerates over a considerable area, in 
conjunction with equally clear evidence of their production with- 
out the assistance of any marked elevation. 
AuG. FP. FOERSTE. 
