324 STRATIGRAPIIICAL GEOLOGY. 



A few details additional to what has been already given will now be in 

 order. The greenish sandstones erop out on the hill south of the Atwood 

 mine, dipping 70° W. By S. C. Simonds's, next the town line, there are 

 hard greenstones, not conglomerate, dipping 65° N. 70° W. There are 

 bands of a white quartzite a little west of the Atwood mine, believed to 

 be the same with the wliite ledges by M. Kimball's, and near the mouth 

 of Salmon Hole brook. In following up this latter stream we find the 

 following order: — First, there are the usual hard dioritic schists of the 

 riuronian, much like those in the railroad cut, being the same layers in 

 fact, dipping 65° north-westerly. These layers contain interesting iron 

 ore nodules, consisting of the specular variety, enclosing hematite, the 

 latter verging into limonite as it decomposes. The ledge is full of holes, 

 caused by the washing out of these iron ore nodules. Close to the rail- 

 road crossing of the stream are micaceous quartzites underlaid by the 

 white rocks. About a fourth of mile back are large blocks of hornblende 

 rock, which are supposed to represent this rock as it continues south 

 from the saw-mill called above "near W. K. Chase's" and the "Whipple 

 Brook" establishment. It must be in jDlace very near. Next comes the 

 slate band, occurring at a bend in the stream quite conspicuously. The 

 remainder of the distance to the display of the Coos slates is mostly cov- 

 ered by drift; but two or three exposures of conglomerate are visible, 

 dipping 60° north-westerly like all the strata upon this brook. This is 

 believed to connect with the coarser "egg" conglomerate at North Lis- 

 bon, but here it closely resembles the auriferous variety so common in 

 Lyman. A micaceous schist occurs with it. No other rock intervenes 

 between this fragmental one and the Coos staurolite slates, which begin 

 to show themselves three fourths of a mile above the Ammonoosuc. It 

 is the place for a narrow band of Huronian to occur between this con- 

 glomerate and the staurolite slates, as appears from the order of succes- 

 sion at North Lisbon. 



Following up the Ammonoosuc, the next outcrop is the massive horn- 

 blende at the saw-mill, coursing in the direction of G. H. Buel's. The 

 first ledge above it is a black slate, with many small veins of quartz, much 

 contorted, and with a strike carrying it squarely across the river. This 

 is thought to be the continuation of the slate just mentioned, and the 

 contortions arc due to local compression. It appears distinctly on the 



