EXPLANATION OF PLATE XIII. 



Fig. I. Diagram map of Rock River near its mouth. Tlie lower part of the 

 diagram is not correct, as it represents the river as too nearly 

 westerly in its course. 

 (I. and b. Points between which sections were made. 



c. Point near which the section represented in Fig. i was taken. 



d. Sand-bar on which the .shells are washed up in great numbers. 



Fig. 2. Section taken at f. Fig. i. 



a, b. c. The three strata: /; and c are stratified and laminated. 



d. Deposit of loose sand. 



r. Surface of water in Rock Riser at low water. 

 P^ig. 3. ir, b, r, d. Pyrs>itlofsisscaltirifotJiiis (Wolf), Call and Pils. X about 5. 



