GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 305 



assay. Hence the name auriferous, as any one of its exposures is likely 

 to yield a trace of the precious metal. At some of the openings pyrrho- 

 tite occurs in considerable quantity, and, in fact, it is apt to occur in any 

 ledge of it. It is not therefore certain whether the gold discovered comes 

 from the pyrites or the quartz ; and if from the latter, whether it consti- 

 tutes a part of the original conglomerate, forming pebbles like those of 

 quartz, or whether it entered with the siliceous infiltrating matter. The 

 constituent fragments were derived from the adjacent auriferous strata, 

 so that the presence of gold in the pebbly condition may be looked for, 

 though the whole of it has not been originated in that way. This con- 

 glomerate is disposed in two groups, corresponding to the main and east- 

 ern subordinate ranges of the Lyman group. Each one is double, or 

 arranged into two parallel lines, as if repeated by undulations in the 

 strata. I will describe the more western ranges first. 



It is singular that this formation should commence so abruptly, and 

 exhibit no traces of its existence to the north of Young's pond ; — yet the 

 enclosing material is traceable with difficulty beyond this point, because 

 it is covered by newer slates, hence the same explanation may account 

 for the concealment of the conglomerate. 



North of the mine of the New England Mining and Reduction Company is an out- 

 crop of the conglomerate 1600 feet long, parallel with the road and a short distance west 

 from it. At the south end it dips 70° S. 67° E. The course of the ledge is N. 23° E., 

 and it may be fifty feet wide. The continuity is broken at the south end of this mass, 

 and, by proceeding S. 30° E. 1160 feet, it is found again about a hundred feet to the 

 south of D. Knapp's house. Proceeding S. 50° W. for about 500 feet, we find an 

 enormous expanse of this rock, attaining 335 feet in its greatest width. The strata 

 are nearly vertical, about 80° south-easterly, rather steeper than appears upon Fig. 31. 

 This part of the formation is flanked on the north-west by green hydro-mica schist, 

 and by Helderberg slates upon the south-east. On account of its superior hardness 

 it occupies the crest of a hill, the highest in the immediate vicinity. It would seem 

 as if this mass must be folded up at least once, in order to account for its great thick- 

 ness. 



The next section of this range exhibits three bends, not including the right angle 

 made by its starting opposite the very thick portion of the mass just described. We 

 have first a bend of about 70° easterly, then of 150° to the west, and a third of over 

 120° to the east again. The length of the range, after leaving the very thick mass by a 

 right angle, is about 140 feet. It then proceeds S. 35° W. after the 70° bend, for about 

 500 feet. Next, for about 700 feet, after bending 150°, it has the course of S. 70° W. 

 VOL. II. 39 



