228 Tertiary. 



In 1872, Dr. Dawson* said, that the Bowlder clay of Canada con- 

 sists of hard, gray clay, filled with stones, and thickly packed with 

 bowlders, and usually rests directly on striated rock surfaces ; though 

 in Cape Breton, a peaty or brown coal deposit, with branches of trees, 

 has been found to underlie it, and in some places there are deposits of 

 rolled gravel beneath it. The stones are often scratched and ground 

 into wedge-shapes, as if by the action of ice. At Isle Verte, Riviere 

 du Loup, Murray Bay, Quebec, and St. Nicholas, on the St. Lawrence 

 it is fossilferous, containing, Leda truncata, Balanus humeri, and 

 Bryozoa. 



In some localities the stones in the Bowlder cla}^ are almost exclu- 

 sively those of the neighboring rock formations, in others those 

 having traveled from a distance predominate ; occasional instances 

 occur where bowlders have been transported to the northward. 

 Though the Bowlder clay often presents a somewhat widel^^ extended 

 and uniform sheet, j'et it may be stated to fill up small valleys or 

 depressions, and to be thin or absent on ridges and rising grounds. 



Beneath the Bowlder clay on the St. Lawrence and the Ottawa, there 

 are two sets of stria, a southeast set, and a southwest set. In Nova 

 Scotia and New Brunswick, as in New England, the prevailing direc- 

 tion is southeastward, though there are also southwest and south 

 striation, and a few cases where the direction is nearly east and west. 

 At the Mile end quarries, near Montreal, the polished and grooved 

 surface of the limestone, shows four sets of striae. The principal ones 

 have the direction of S. 68° W. and S. C0° W. respectivelj^ and the 

 second of these sets is the stronger and coarser, and sometimes oblit- 

 erates the first. The two other sets are comparatively few and feeble 

 strife, one set running nearly north and south, and the other northwest 

 and southeast. These last are probably newer than the first two sets. 

 The locality is to the northeast of the mass of trap constituting the 

 Montreal mountain, and evinces that the movement must have been up 

 the St. Lawrence, which is the dominant direction of the strife in this 

 valley. It is the Bowlder clay connected with this S. W. striation, 

 that is rich in marine fossils. 



At the mouth of the Saguena^', near Moulin Bode, are strife and 

 grooves on a magnificent scale, some of the latter being ten feet wide, 

 and four feet deep, cut into hard gneiss. Their course is N. 10° W. 

 to N. 20° W. magnetic, or N. 30° to 40° W. when referred to the true 



* Post-pliocene Geol. 



