HISTORY OF DERRYFIELD. 35 



RHODODENDRON SWAMP. 



About two miles northwest of Amoskeag falls, lying to the 

 east of and near the valley of Black brook, is a great thicket, 

 covering from sixty to eighty acres, and known as Rhododendron 

 or Cedar swamp. A portion of this territory is covered with a 

 thick growth of cedars, and large areas are overgrown with rho- 

 dodendron. So dense is the cover that its depths are penetrated 

 with difficulty, but it is visited by scores of people whose time 

 and toil are rewarded in securing specimens of this rare and 

 fragrant flower. 



POT-HOLES AND ROCK Vi^EAR. 



The vicinity of Amoskeag falls, below the present dam, pre- 

 sents fine examples of the well-known but little understood pot- 

 holes, found there in great number. These are of all sizes and 

 depths, from those of a few inches in diameter or groove to those 

 of .several feet in width, and of varying depth. The largest 

 example is located high upon the sloping shoulder of a great 

 boss of granite, lying south of the highway bridge, between the 

 two main streams leading from the dam, and overhanging the 

 current. Here may be seen a large excavation running down 

 entirely through the east shoulder of the rock, the rapid water 

 having worn away the ledge beneath, allowing the stone tool or 

 tools which performed the work to drop through into the stream 

 below. This curious hole is nearly circular in form, more than 

 six feet in diameter, and not less than fourteen feet in depth. 

 Since this remarkable excavation was made a large angular frag- 

 ment of rock has fallen into it and lodged about half-way down, 

 where it is now securely wedged in place. This pot-hole — if, 

 indeed, it be such — offers a notable exception to the remaining 

 members of the group and is a geological puzzle. The top of 

 the rock in which it occurs is high above ordinary flood-mark 

 and has not been completely covered by the waters of any fresh- 

 et of modern times, with possibly two or three exceptions, and 



