138 GEOLOGICAL SKETCH OF THE ESTUARY AND FRESH WATER DEPOSIT OF JUDITH RIVER. 
of an aggregation of casts of Melanias and large bivalves like Unios, held together by a 
slightly coherent, fine, gray calcareous clay, and indicates a fresh water deposit in that 
region very similar to that of the Bad Lands of the Judith. Mr. Drexler informs me, 
that the strata were uplifted and tilted in every direction like the beds of the Judith de- 
posit, and the evidence indicates to my mind a fresh water formation of Lower Cretaceous 
or Upper Jurassic Age. We can thus see, that we have, as yet, but caught a glimpse of 
the interesting discoveries which await the geological explorer in the Far West. 
