306 STRATIGRAPHICAL GEOLOGY. 



After bending 120° it runs S. 30° E., about 480 feet, when it sinks beneath the allu- 

 vium. The valley of a brook intervenes next. As it then crops out, having the same 

 direction for more than 500 feet, after a short concealment, it must be continuous for 

 the whole distance of a third of a mile. The next bend makes an angle of 110°, and 

 the course is to the west for an eighth of a mile. At the next angle there is a subordi- 

 nate bend, and the ledge courses for an eighth of a mile about S. 30° E. to the house 

 of Horace Aldrich, situated upon the road from Lisbon to Parker hill, and at the place 

 where a road branches to Young's pond, passing by the New England Company's mine. 

 The width of the conglomerate, after the first quadrangular bend to Aldrich's, is from 

 thirty to sixty feet. The delineation of the portion just described is not quite so accu- 

 rate as that which follows, and I shall now rely more upon reference to the map in 

 speaking of its continuation. 



On the south-west side of the road from Aldrich's, upon an eminence and enclosed 

 within an area of 500 feet square, is a series of twists too intricate to be described 

 minutely. Upon looking at this and other similar bendings, one feels as if the original 

 formation was like an elastic string in a state of strong tension, when it broke, and 

 both ends suddenly recoiled and assumed a doubled-up appearance. The more south- 

 ern part of this twist is a loop with the sides parallel to each other, the course being 

 about north and south. The width of this rock in the road is sixty feet ; the other 

 extremity is about half as thick. The rocks bordering the curves conform to them, 

 consisting of dolomites and slates. The probable continuation of the south end of the 

 loop is to be found 550 feet distant, 275 feet east of V — 10, it being the end of a mass 

 275 feet long and twenty wide, running about S. 35° W. 



Next, there are numerous outcroi^s of conglomerate, averaging twelve or fifteen feet 

 in width, in all respects similar to the wider bands, but when joined together continu- 

 ously they more than fill out the gap between the exposures of the larger ledges. For 

 the present, I think they belong to the same band continued southerly, or to what was 

 originally more shallow water in the ancient sea where the rock grew. The first expo- 

 sure at V — II would connect well with those in the 500-feet square area, after the inser- 

 tion of the piece that has travelled past V — 10. These are doubled, and, after passing 

 south-westerly 275 feet, another ledge is found 125 feet long. The space between is 

 occupied by ledges of green and white schists, so that we cannot suppose the conglom- 

 erate continues beneath the soil. The next space of 250 feet S. 35° W. from V — 11, is 

 covered with earth. Then succeeds a continuous exposure of the narrow conglomerate 

 for 1400 feet, with two acute angular bends, the extreme distance of the remotest points 

 from each other being 740 feet. We find dolomite upon the east and south sides of this 

 band. Between the northern end of this long crooked string and the southern end of 

 the next development of the broader band of conglomerate, a distance of 260 feet, 

 there are three fragments of the rock, disposed at different angles, which would neatly 

 fill up the gap if placed in the proper position. 



The next fragment in order belongs to the greater range, and lies nearly between the 

 lines 12 and 14, the eastern end extending 100 feet beyond 12. The other limiting 



