32 On Bowlders and Rolled Stones, 



westerly part of Danbury, where we leave the apparent 

 course of the ocean current, and pass over rising ground 

 to the head waters of a siiiall branch of Black River, where 

 there is a great deposit of Breccia both in place and in 

 loose blocks, some of the pieces of which are partially 

 rounded. The little fragments of the rock are very white, 

 and their angles almost invariably quite perfect, and what 

 perhaps is singular, they are cemented by granite;* the 

 two rocks alternate with each other in place, a fact which 

 is also seen sometimes in the rounded rocks. As you de- 

 scend the stream and valley, they are plainly more and more 

 rounded, and at Black River, about four miles, there is 

 hardly a rock of any other kind ; some are of niany tons 

 weie;ht, and from that down to small gravel, and even the 

 sand and gravel of remaining hills or ridges, sixty or sev- 

 enty feet high, are composed almost entirely of this kind of 

 rock The rivulet that descends into this valley is but a 

 small mill stream at its junction with Black River in Ando- 

 ver, and never could have had any agency in rounding, 

 carrying down and depositing such an immense mass of 

 rocks, gravel, and sand. In the course of Black River for 

 a mile or two, nearly all the sand banks and hedges and the 

 gravel and rounded rocks continue of the same kind. 

 They then begin to diminish, and the fine gravel and sand 

 soon disappear, but the rounded rocks are seen more or less 

 every where on the ground and in the banks. In passing 

 over Salisbury Hills, frotn five to ten miles below (which 

 are from one to two hundred feet higher than Black River) 

 these rocks well rounded at first, compose nearly one half 

 of the stone fences, and are every where seen in the Hills 

 although sensibly and gradually lessening in proportion to 

 other rocks, so that before leaving Salisbury, the stone walls 

 are composed of only about 4 or J of them. Quitting these 

 hills, the traveller descends to the extensive plain of sand in 

 Boscawen and Concord where few rocks are to be seen, 

 and those are generally granite. After leaving these plains in 

 Pembroke, on the opposite side of Merrimack River, we still 

 find rounded rocks of the same kind, but so few that only one 

 occurs in two or three rods of stone wall, this is about thirty 

 miles from their original situation. In taking here the London- 



* Perhaps by a re-aggregation of its constituent minerals, quartz, feldspar 

 and mica. — Ed. 



