CENOZOIC TIME — QUATERNARY. 



903 



to 30 feet; and the kettle-lioles are numerous along its borders. It was the 

 coiirse of a deep treuch made by the southward-moving glacier; and the 

 depression over the site of tlie trench was left in the sand deposits made in 



1555. 



Kettle-holes in the New Haven Terrace formation, n igures indicate the height above the sea level. 



1 inch = I mile. 



the trench. The trench was too deep to be filled to the ordinary level of the 

 plain by the deposition of the sand and gravel, and hence its present depth 

 of 20 to 30 feet ; and the kettle-holes, which border, blend with, and intervene 

 between them were probably formed under the same conditions. (Pages 

 186, 193.) 



ELEVATION CLOSING THE CHAMPLAIN PERIOD. 



The elevation of the land which closed the Champlain period was of great 

 extent over ISTorth America. The high- level shore-lines already described 

 are the evidence, they marking both the limit of the Champlain subsidence, 

 and the fact, though not necessarily the Umit, of the following elevation. Not 

 the limit ; for the present height of these elevated shore-lines is the final 

 height after whatever oscillations of level may have in the mean time 

 occurred. The movement may have earned the land up to a much higher 

 level and returned it to its present position without leaving any distinct 

 record. 



The change in level was attended by a change also in climate, from a warm 

 climate to the cooler of modern time ; but to a climate even cooler than now 

 if the level at the first was higher than now. It is certain that there was no 

 return of the ice-sheet ; but evidence of less extreme cold may jet be found 

 about the local glacier areas of the Rocky Mountains, and possibly about the 

 White Mountains of New Hampshire. 

 Dana's manual — 63 



