DETAILS OF SECTIONS. 27 



example of a modern beach. (See Plate III.) Some other features of the surface 

 geology of that region I have delineated, and shall notice farther on. 



A slight examination led me to the conclusion that the terraces are of unusual 

 interest upon Ammonoosuck river, which comes from the White Mountains and 

 empties into the Connecticut. 



I have followed up the Waterquechee river in Vermont to a considerable distance, 

 and find some interesting terraces a little below the village of Quechee, where is a 

 wild gorge. Above this not less than seven terraces occur on the southwest side 

 of the stream, and four on the opposite side, as I have indicated simply by lines 

 upon Plate III., connected with my paper on the marks of drift and glaciers. 



On the same map I have sketched most of- the terraces on Deerfield river above 

 Shelburne Falls, where the Ghor terminates. Generally, we have along this 

 stream only two terraces, as represented, though sometimes more exist, as section 

 34 shows, to be described below. But where small streams enter Deerfield river, I 

 have noticed fine examples of the Delta Terrace, and several of these are marked 

 upon the map, and will be more particularly described further on. 



I now proceed to describe Section No. 34, just referred to, as well as several 

 others, mostly of beaches out of the Connecticut valley. 



34. Beyond the barrier across Deerfield river a little west of Shelburne Falls, 

 commences a rather broad- valley, which must have been once a lake, extending 

 perhaps fifteen miles, to the foot of Hoosac mountain. Here, as we might expect, 

 we find good examples of terraces. I have measured, however, only a single series, 

 lying on the south side of Deerfield river, and at the mouth of a small tributary 

 coming in from the south through Buckland. It will be seen from the section, No. 

 34, that the terraces are all of them low. They seem to be the result of the joint 

 action of both rivers. 



35. In the southeast part of Heath is a mountain, to which the Indian name of 

 Pocumtuch was formally given in 1855, by the Senior Class in Amherst College 

 who graduated in 1856. It was used as a station in the trigonometric survey of 

 Massachusetts, and consequently its height above tidewater is known to be 1888 

 feet. From this point I levelled northwesterly about two miles, till I struck a 

 deposit of water-worn sand and gravel, of limited extent, but which I must regard 

 as an ancient beach; for I know not how else to explain the occurrence of commi- 

 nuted and sorted materials in a spot so elevated and open to the surrounding 

 country. The section will give an idea of its position. 



36. The summit-level of the Western Railroad, in Washington, is 1456 feet 

 above the ocean; the cut in the rock being 60 feet. On all sides of this cut I find 

 deposits of sand and sometimes gravel, at least to the height of 134 feet above the 

 original rock. This would give 1590 feet above the ocean as the highest mark of 

 distinct sea action at this place, although very probably similar deposits can be 

 found in the vicinity at a higher level. But I am a little doubtful as to some of 

 these banks of sand; for the rock here is a variety of gneiss easily disintegrated, 

 and the result of the disintegration is coarse sand. I cannot thus explain, however, 

 the thicker deposits, certainly not those with pebbles, and these are seen nearly at 

 the height above named. 



