No. 3.] DAWSON — POST-PLIOCE\E. 243 



1. Sand and G^rayeZ, capping the terraces cut in the previous 



deposits, aud forming slight ridges or eskers in some of 

 the lower levels. It contains on the lower terraces a few 

 shells of Leda and Tellina. At the bottom of this de- 

 posit there are seen in places many large boulders of 

 Laurentian and Lower Silurian rocks, resting on the 

 Leda clay below. 



2. Leda Cknj^ exposed in the railway cutting and seen also in 



the edge of the second terrace. Thickness one hundred 

 and twenty feet or more. It holds a few large boulders 

 and shells of Leda truncata — the latter uninjured and 

 with the valves united. 



3. Boulder clay, or hard gray till, with boulders and stones. Seen 



in a mill-sluice near the bridge, and estimated at twenty 

 feet in thickness, at this place ; though apparently in- 

 creasing in thickness farther to the westward. 



4. Shales of Lower Silurian age, seen in the bottom of the 



River near the bridge. They are smoothed over, but 

 show no striae, though they have numerous structure lines 

 which might readily be mistaken for ice-strise. 



To the eastward of the mouth of Trois Pistoles River, the 

 first terrace above-mentioned is brought out to the shore by a pro- 

 jecting point of rock. In proceeding westward toward Isle Verte, 

 it recedes from the coast, leaving a flat of considerable breadth, 

 which represents the lowest terrace seen on this part of the St. 

 Lawrence, and is elevated only a few feet above the sea. This 

 flat is in many places thickly strewn with large boulders, probably 

 left when it was excavated out of the clay. In proceeding west- 

 ward the first or railway terrace of Trois Pistoles, inland of the 

 flat above mentioned, is seen to consist of Boulder-clay, either in 

 consequence of this part of the deposit thickening in this direc- 

 tion, or of the Leda clay passing into Boulder-clay. It still, 

 however, at Isle Verte, contains a few shells of Leda truncata 

 in tough reddish clay holding boulders. 



Riviere-diL-Loup and Cacouna. — The country around Cacouna 

 and Riviere-du-Loup rests on the shales, sandstones, and con- 

 glomerates of the Quebec and Potsdam groups of Sir W. E. 

 Logan. As these rocks vary much in hardness, and are also 

 highly inclined and much disturbed, the denudation to which 

 they have been subjected has caused them to present a somewhat 



