GEOLOGY OF EAST BOSTON. 449 



farther inland, though here and there reach- 

 ing the sea-coast, we have unchanged glacial 

 drift deposit. At some points the alteration 

 is so slight as to denote only a momentary rise 

 of the sea. Under these circumstances one 

 would naturally look for fossils in the drift, 

 and M. Desor, in company with M. de Pour- 

 tales, was the first to find them, at Brooklyn, 

 in Long Island, which lies to the south of 

 New York. They were imbedded in a glacial 

 clay deposit, having all the ordinary charac- 

 ter of such deposits, with only slight traces 

 of stratified sand. It is true that the greater 

 number of these fossils (all belonging to spe- 

 cies now living on the coast) were broken into 

 angular fragments, not excepting even the 

 thick tests of the Venus mercenaria. . . . 



The suburb of Boston where I am living 

 (East Boston) is built on an island, one kilo- 

 meter and a half long, extending from north 

 to southeast, and varying in width at differ- 

 ent points from two to six or seven hundred 

 metres. Its height above the sea-level is 

 about sixty feet. This little island is com- 

 posed entirely of glacial muddy deposit, con- 

 taining scratched pebbles mixed with larger 

 boulders or blocks, and covered also with a 

 considerable number of boulders of divers 



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