28 SURFACE GEOLOGY. 



This spot was doubtless one of the lowest, if not the lowest, pass through the 

 dividing ridge between the Hudson and Connecticut rivers, and therefore we should 

 expect marks of sea action here, if the ocean once stood above the mountains of 

 New England. 



37. French's Hill, in Peru, on Hoosac Mountain, is one of the highest peaks in 

 Massachusetts, and as its height was ascertained in the trigonometric survey, I 

 visited the spot in the hope of finding beaches or terraces in the vicinity, whose 

 height, also, above the ocean, could be easily determined. The section No. 37 

 exhibits the result. By carrying a level downward from the top of French's Hill 

 we strike what I conceive to be an ancient beach, 217 feet below the summit, or 

 2022 feet above the ocean. It is level like a terrace, but the materials are not 

 very thoroughly rounded, like those of the lower beaches and terraces; yet they 

 are more worn than drift usually is, and I can impute the level top of the deposit 

 to water only. 



Passing eastward from this beach, we cross a brook, which rises in a pond, and 

 then go over a hill of considerable height. In descending it easterly, I fancied the 

 existence of another beach; but, going onward, nearly three miles from French's 

 Hill, and descending about 470 feet, we reach a small stream, where are at least 

 three terraces, made up of coarse materials, sand, gravel, and bowlders, the highest 

 on the west bank being 85 feet above the stream, and 1852 feet above the ocean. 

 This is the highest river terrace I have yet met with in New England ; but I see 

 no reason why they may not be found at a higher level in some of our mountains, 

 since, as I conceive, they are mainly the result of the action of the stream itself. 

 In this instance, however, it is rather difficult to imagine the former existence of 

 any barrier high enough to shut in the water, so that it would overflow these ter- 

 races : so that probably the sinking of the waters of the ocean may have had an 

 important influence on their production. On the east side of the stream are three 

 terraces of about a corresponding height, but I did not measure them. 



Proceeding eastward from this elevated region, I met with other deposits at a 

 lower level, more obviously once constituting the shores of an ocean ; but not then 

 having barometers with me, I could not measure their height. 



In going westward, also, from Peru, or any other culminating point of Hoosac 

 Mountain, into the valleys of Berkshire County, we meet with many examples of 

 comminuted and rearranged drift, in the form of beaches, and in the valleys of 

 terraces. But I have not measured the height of these, save a single example on 

 the Western Railroad in Dalton, which I find by the aneroid barometer to be 1228 

 feet above Hudson river. 



In the west part of Whately, on the ridge between that town and Conway, I 

 found a distinct beach of sand and gravel, which by the aneroid and siphon 

 barometers I ascertained to be 697 feet above Connecticut river, and 802 feet 

 above the ocean. In the northwest part of Conway, called Shirkshire, I found 

 another, of coarse gravel and sand, 935 feet above the river, and 1040 above the 

 ocean. Two miles further west, in Ashfield, is another, mostly of sand, 976 feet 

 above Connecticut river, and 1081 above the ocean. A mile further north, an im- 

 perfect beach shows itself, 1216 feet above the river, and 1321 above the ocean. 



