GLACIAL DRIFT, 337 



with water. Why should the former be so much and the latter so little 

 oxidized? Relief came by examining the analyses. The blue clay con- 

 tains more sesquioxide than the lower till, just as would be expected from 

 the nature of the deposit. Furthermore, all blue protoxide clays have 

 come from deposition in water; — hence there is nothing abnormal in be- 

 lieving in the origin of the lower clay from the older till. 



Order of Events. 



The following list of occurrences expresses our most recent opinions 

 respecting the order of events occurring in New Hampshire in the Gla- 

 cial, Champlain, and subsequent periods : 



1. The country was covered presumably with forests of late Tertiary 

 type, partly exhibited to us by the nearest fossils, yet of Eocene age, in 

 Brandon, Vt. The beech, bass-wood, buckeye, Aristolochia, peperage, 

 and cinnamon have been found there, with some others allied to the 

 conifercB. The change of climate induced by the change of land, com- 

 bined with astronomical causes, would destroy most of these plants, and 

 render the region sterile. Then the ice commenced to spread over New 

 England, with alternate meltings of limited extent, so as to give rise to 

 beds of sand and gravel. 



2. The ice accumulated in the St, Lawrence valley so as to flow over 

 New England, possibly preceded by a south-west current. The whole 

 country would have been covered by a sheet of ice, thousands of feet in 

 thickness, — probably 7,000 or 8,000 feet in the lower part of the state, — 

 flowing south-east towards the ocean. This was the period of the forma- 

 tion of the lower till, and of the great terminal moraines of lower New 

 England. The broad sandy plains of Cape Cod and Long Island mark 

 the beginning of the Champlain period. 



3. The melting of the ice has progressed steadily until no more ice is 

 supplied from the St. Lawrence valley. New Hampshire is now covered 

 by local glaciers, pushing down the Connecticut, the Merrimack, and 

 other streams. The lower fossiliferous deposits of the coast are coeval 

 with these glaciers. Variable seasons cause temporary advances and 

 retreats of the ice, and thus allow of conditions favorable to the produc- 

 tion of the inter-glacial beds. 



4. The thermal influences prevailing, the ice is driven back to the 



