68 J. D. Dana on the origin of some of the 



of its melting, and which belong to the oj^ening part of the Champlain 

 era may be first considered ; and afterward the secondary and later 

 results. 



1. Events and results of the Opening Champlain era. 



1. Depositions over the hills. — The deposits over the hills in the 

 New Haven region, consist, like those of the rest of New England, of 

 sand, stones, and large boulders, mingled pell-mell, or without strati- 

 fication, except wliere they fell into lakes and rivers. 



This unstratified drift is found wherever the land rises above the 

 level of the stratified " alluvium " of the New Haven plain, except 

 along the upland valleys. In some places it appears to be more or less 

 stratified, as near the Seymour turnpike (running west from Westville) 

 after passing the first hill (that of the Edgewood line) ; but in this and 

 other similar cases the stratification is owing to the fact that the region 

 in the time of the melting glacier was the course of a flooded stream. 

 The boulders and stones are not to be looked upon as lying just where 

 they were dropped in all cases, nor as being formerly in the same large 

 numbers as now over given areas ; for the sands and smaller stones 

 that fell with the larger masses have to a great extent been washed 

 away to lower levels, and carried off by streamlets to rivers, and by 

 rivers seaward, and thus the large stones that cx-owd the surface in 

 some regions may when first dropped, have been many feet apart, or 

 even scores of feet away from the spot where they now lie. 



The character of the stones and the size of the boulders over the 

 hills show what is the nature of much of the material which fell into 

 the waters, and which now lies over what was the bottom of the bay 

 in the Glacial era. 



The larger boulders of the New Haven region consist mostly of trap 

 and sandstone ; and next to these in size and numbers are those of 

 gneiss and quartz. Those of trap, sandstone and gneiss are quite 

 numerous over the western border of the region, especially along the 

 eastern margin of the Woodbridge plateau ; those of quartz rock have 

 a very wide distribution. Only a few of gneiss have been observed 

 as far east as Sachem's ridge. 



Some of the largest of the trap boulders are as follows : 



One 2^ m. north of Westville, on Boulder Hill, measuring along its 

 diameters 29, 14 and 12 ft. and weighing at least 400 tons. 



The boulder in pieces making the Judges' cave (the place of con- 

 cealment of the regicide judges for a while in 1661), If m. east of 

 south of the preceding, on the top of the West Rock ridge, the masses 

 when together having weighed at least 1000 tons. 



