TERRACES. 7 



2. Ascending to a second terrace, we almost invariably find it composed of coarser 

 materials; or, perhaps more frequently, of sand at the top and clay at the bottom; 

 though sometimes the sand is all removed. (See B on Fig. 1, Plate XI.) 



3. Rising to a third terrace, we usually find a mixture of sand and gravel; the 

 latter not very coarse, the whole imperfectly stratified, and also sorted; that is, the 

 fragments in each layer have nearly the same size; as if the waters that removed 

 and deposited the materials, had a different transporting power for each stratum. 

 (See C, Fig. 1, Plate X.) 



4. A fourth terrace is sometimes found still higher, differing from the last only in 

 being of coarser, but still of decidedly water-worn materials. (D, Fig. 1, Plate XI.) 

 There is another important distinction. Hitherto the tops of the terraces have been 

 for the most part level, unless worn away by agents subsequent to their formation. 

 But now we find their surface not unfrequently piled up into rounded or curved 

 masses with corresponding depressions, resembling what is called a chopped sea, 

 or the eminences and anfractuosities on the surface of the human brain. The 

 depressions are not valleys, which might have been made by currents of water, but 

 irregular cavities, often a hundred feet deep, or more, usually not more than twenty 

 or thirty, and perhaps more frequently not over ten or fifteen. Yet the materials 

 forming the boundaries of these depressions are always water-worn and sorted, 

 either sand or gravel. These irregular cavities and elevations do not always 

 appear in connection with the fourth terrace, but sometimes with the fifth and 

 sixth. Yet I believe there is never a level-topped terrace above them (that is, 

 older) in the same series; and they are always below the beaches. They are a 

 singular feature in the terrace landscape, and are among the most difficult of all 

 the phenomena of these formations to account for satisfactorily. I shall of course 

 recur to them again in a subsequent part of this paper. (See D, Fig. 1, Plate XI.) 

 Plate IX, Fig. 3, is a sketch taken in the west part of Pelham, in which we see the 

 more perfect lower terraces, succeeded by others having the peculiarity of outline 

 above described. Such sketches, however, give but a faint idea of these moraine 

 terraces, as I now call them. They are shown also imperfectly on Plate IX, Fig. 2, 

 taken in Russell, on Westfield river, with the Pentagraph Delineator, by Mr. 

 Chapin, its inventor. 



5. Above the irregular terrace just described, we find other accumulations of 

 decidedly water-worn materials, generally coarser, the fragments of rolled and 

 smoothed rock being sometimes a foot or two in diameter ; yet still more or less 

 sorted, so as to bring together those of a determinate size, or rather those not 

 exceeding a certain size. Coarse sand, however, constitutes the greater part of the 

 deposit, and sometimes the whole of it. Its outline is rounded, rarely with a level 

 top for any considerable distance. Yet in its longest direction it maintains essen- 

 tially the same level, and often may be seen for many miles at the same height, 

 and more or less worn away, as a fringe along the sides of the hills that bound a 

 valley ; appearing, in fact, as if these deposits once formed the beaches of estuaries 

 that occupied those valleys; and such I suppose they were. (See Fig. 1, E, Plate XL) 



As we rise above the most recent ancient beach, we find others at different 

 levels, of materials less water-worn, more irregular in their form, and less con- 



