BOTANY, CONCHOLOGY, AND GEOLOGY. 51 



mounds or moraines, composed of material ground up 

 and borne down by the glaciers from a northwesterly- 

 direction. Thus during the glacial or drift epoch, the 

 whole region of Southern New England was elevated 

 at least six hundred feet above its present height, and 

 this uptilting of the eastern part of our continent pushed 

 the Atlantic back some seventy miles south of where it 

 is now, entirely out of sight from Quanaty. And thus 

 Nantucket stood high and dry as one of a series of 

 hills, rather than islands, surrounded by the lower 

 lands of what are now the bottom of the sounds at the 

 north, and the St. George's Banks at the east and 

 south. Then, when subsequent to the deposit of the 

 Nantucket heap of drift stuff, the continent, on which 

 as a heap it stood, sank, the sea gradually advanced 

 till it beat at last as far north as Surf side and 'Sconset, 

 and poured round into the sounds, leaving Nantucket 

 and the Vineyard standing out as islands at last, and 

 giving at the same time also their insular state to 

 Block, Long, and Staten Islands. 



So much for the geologic period when Nantucket 

 was formed: first as a high and dry mound, standing 

 seventy miles north of the southern coast of New 

 England, and subsequently, by the sinking of the land 

 on which it stood, as an island. The period was be- 

 tween the end of the tertiary era and the present time, 

 at and after the epoch known as the drift or glacial. 



Next we may, in the light of the most recent con- 

 clusions in science, briefly glance at the causes which 

 led to the formation of the spot where we were born. 



In all probability the home from w T hich the vast 

 glaciers started, that covered so much of our continent 



