DETAILS OF SECTIONS. 17 



of coarse sand, which I regard as an ancient beach, and have so marked it on the 

 map (Plate VI, Fig. 2). 



11. On the north side of the stream (Fort river) the terraces are more nume- 

 rous than on the south side, and in general they do not correspond in height. I 

 have, therefore, been obliged to give another section (No. 11), extending from Fort 

 river, in Amherst East Village, to the sandy sea-beach above described, 546 feet 

 above Connecticut river. The course of this section, and also that on the south 

 side of the stream, are indicated by the succession of figures on the map. On the 

 north side the terraces rise highest at the southeast point of Mount Hygeia, evi- 

 dently because there was once a barrier at this spot, at least a partial one, which 

 would cause the materials drifted by the current to accumulate. The depression 

 shown by the section, still further east, was doubtless made by the action of the 

 small stream, as it wore away the barrier. In other words, it was a pond which 

 was gradually drained, and so the terraces were formed. 



It is not easy to say whether No. 17 be a terrace or a beach. It is coarse sand 

 and gravel, and is somewhat level-topped : yet it passes into a decided beach 

 further south, and I have marked it as such. When the ocean stood as high as 

 046 feet above Connecticut river at this spot, it must have produced a small bay 

 opening to the north ; Mount Hygeia forming the right hand side and Pelham Hill 

 the left. Nearly 400 feet higher, we find another beach, which, on the general 

 map, I have represented as extending through Shutesbury, several miles to the 

 north. It can be traced a great distance, and probably might be found extending 

 into New Hampshire. In Shutesbury it is very distinct, and more sandy than in 

 Pelham, where, at its highest line, the rolled fragments are sometimes a foot in dia- 

 meter. By carrying a level from Packard's Hill, in New Salem, the height of which 

 has been accurately determined in the Trigonometrical Survey of Massachusetts, I 

 found the most distinct beach in Shutesbury to be 1082 feet above Connecticut river. 

 This corresponds nearly to a third beach on the east side of Pelham Hill, half a 

 mile south of the Congregational Meeting-house, on the road to Enfield, which is 

 1049 feet above Connecticut river. Between these two highest beaches in Pelham, 

 most of the surface is covered by ordinary drift, with rocks in places (gneiss) occa- 

 sionally shooting through. Drift, also, appears between the lowest and the second 

 beaches. 



This section across the Connecticut valley I am convinced gives us a good idea 

 of the character of a large part of the valleys of New England and New York, 

 and perhaps of the whole country, with the exception of drift. Wherever I have 

 travelled, since my attention was turned to the subject, I find terraces in the lower 

 part of the valleys, and similar though usually coarser materials arranged beach- 

 wise, on the flanks of the mountains and hills, especially where spurs of the ridges 

 form spots that might once have been bays, in which sand and gravel would natu- 

 rally be accumulated on the shores of a lake, or the ocean, by winds and waves. 

 There are scarcely any mountains of New England so high that this work has not 

 reached their summits. But further on I shall have occasion to point out other 

 particular examples. 



The section of terraces on the north side of Fort river, passing most of the way 



