230 Tertiary. 



on the movement of tides and currents. In some instances, as at Cote 

 des Neiges, near Monti'eal, and on the terraces on the Lower St. Law- 

 rence, it is obviously merely a shore sand and gravel, like that of the 

 modern beach. 



The terraces and inland sea cliffs have been formed by the same 

 recession of the sea which produced the Saxicava sand. At Montreal, 

 where the isolated mass of trap, flanked with Lower Silurian beds, 

 constituting Mount Roj^al, forms a great tide-gange for the recession 

 of the Post-pliocene sea, there are four principal sea margins, with 

 several others less distinctlj'' marked. The lowest of these, at a level 

 of 120 feet above the sea, corresponds, in general, with the level of the 

 great plain of Leda clay in this part of Canada. On this terrace, in 

 many places, the Saxicava sand forms the surface, and the Leda clay 

 and Bowlder clay may be seen beneath it. Another at 220 feet in 

 height furnishes Saxicava sand resting on Bowlder clay. Three other 

 terraces occur at heights of 386, 440 and 470 feet, and the latter has, 

 at one place, above the village of Cote des Neiges, a beach of sand and 

 gravel, with Saxicava and other shells. Even on the top of the 

 mountain, at a height of about 700 feet, large traveled Laurentian 

 bowlders occur. 



The prevalent Post-pliocene deposit on Prince Edward Island is a 

 Bowlder clay, or in some places bowlder loam, composed of red sand- 

 stones. This is filled with more or less rounded and striated bowlders 

 of red sandstone, derived from the harder beds of the island. At 

 Campbell ton, however, in the western part of the island, a bed of Bowl- 

 der clay is found filled with bowlders of metamorphic rocks, similar to 

 those of tlie mainland of New Brunswick. Striae on the northeastern 

 coast of the island have a direction S.W. and N.E. ; and on the south- 

 western coast S. 70° E. 



At Campbellton, in the sand and gravel above the Bowlder clay, 

 Tellina greenlandica occurs, at an elevation of about SO feet above the 

 sea. On the surface of the country, there are numerous traveled 

 bowlders. Those of granite, syenite, diorite, felsite, porphry, quartzite 

 and coarse slates ai'e identical, in mineral character, with those which 

 occur in the metamorphic districts of Nova Scotia and New Brunswick, 

 at distances from 50 to 200 miles to the south and southwest; though 

 some of them may have been derived from Cape Breton on the East. 

 Those of gneiss, hornblende schist, anorthosite and labradorite rock 

 must have been derived from the Laurentian rocks of Labrador and 

 Canada, distant 250 miles or more to the northward. 



