280 BOARD OF AGRICULTURE. 



75° S. 10° E. Proceeding westerly for several miles, we cross the 

 strata obliquely. Near S. C. Pratt's house in West Foxcroft, the 

 slates are considerably argillaceous, dipping 68° S. 10° W. Near 

 the west line of Guilford, on the south side of the Piscataquis river, 

 the schists have somewhat of the character of a fine sandstone, 

 dipping 85° S. 10° W. At the village of Abbot, the rock is firmer 

 and has the appearance of schists. Here it dips 70° southerly. 



Clay Slate Formation. 



At the crossing of the Piscataquis river in the north part of the 

 town, we come*to a different formation, to the clay slate, whose 

 presence is indicated both by the highly argillaceous character of 

 the rock, and the change in the position of the strata. These are 

 both vertical and inclined N. W. 75°, a change in the strike also of 

 45° degrees. This ledge shows also, a number of the markings of 

 an ancient glacier coming down the Piscataquis river from Blach- 

 ard — a south-east course. We distinguish these markings from 

 the common drift scratches, because these grooves have been made 

 upon the perpendicular side of the ledge, ae well as upon the top, 

 and because they descend the valley, following the course of the 

 stream. Here also are spiral pot-holes, excavated by the eddying 

 rush of the water as it descends ; or, such as are called in Oxford 

 county "screw auger" holes. The water falls a considerable at 

 the bridge. 



Two miles south of Monson village the strata dip 80° N., and 

 consist of clay slate alternating with argillaceous sandstones. At 

 the village the strata dip 75°N. 20° W., and the rock is a little 

 micaceous, but has a very fresh look, though often paler than most 

 of the formation. We kept on the lookout for fossils, but discov- 

 ered none in the brief time devoted to the search. We anticipate 

 the discovery of many fossils in this formation in the future, espec- 

 ially of Nereites. In the north part of Monson, we find ledges of 

 a beautiful clay slate dipping generally 85° N. 15° W., and occa- 

 sionally S. 15° E. or 90°. On all the hills the ledges are exposed 

 beautifully, particularly upon the northern slopes. Wherever seen 

 they are as smooth as a house floor, having been ground down by 

 the ice of the drift period. The ledges are all of a dark bluish cast, 

 and are highly argillaceous. Oiie would think that in this vicinity 

 admirable quarries of roofing slate might be worked. At Spectacle 

 pond, near the north line of Monson, the drift striae run N. 20° W. 



