44 GEOLOGY OF THE TfflRD DISTRICT. 



the Noses. Some of the layers at Amsterdam are referable to this mass, as well as a large 

 portion of the rock quarried at Schelpintown. 



In all these localities, the color of the rock is grey, lighter or darker in some than in others ; 

 hu a crystalline grain ; rather tough, and not so easy to work as the birdseyc. Some por- 

 tions contain knobs, the result of accretionary action, round which shale has accumulated. 



The rock at Stanton's is a very sohd mass, with very few divisions or layers ; of a light 

 grey color, and crystalline. Some of tlie layers or portions are over six feet thjck. The 

 lower layer is nearly seven feet thick ; the next, four ; the upper, about two. The rock is 

 of good quality, witli fewer knobs or accretions than in some of the other localities, and with 

 more of tlie birdseye character than in the other quarries. The surface of the rock is water 

 worn, being quite smootli in some places, and scratched, the direction of the scratches nearly 

 east and west. 



The limestone at Putnam's differs little from that of the quarry below the railroad. Its 

 color is darker, hut the mass is of the same thickness, and the layers arid structure are 

 similar. The top of some parts of the upper layer is bent downwards, owing probably to a' 

 want of uniformity in the material of the rock, some portions settling more than others, which 

 is one of the principal causes why the lines of divisions in rocks are not always straight lines. 

 The more homogeneous the rock, as is evident in some of the masses of the birdseye, the 

 more straight the layers. Where it is mixed with shales, the layers are less straight. 



One of the lower layers at Putnam's quarry, shows some scattered irregular pebbles, 

 forming masses or accretions having the same character in all respects as the yellow-colored 

 calciferous sandrock, and accurately resembling those observed in the quarry at Schelpintown ; 

 the largest of them are fully four inches in diameter, and of greater length. 



These quarries are extensively worked, the stone being quarried for the aqueduct near the 

 Cehoes. There is no better rock in the State for a work of the kind, due care being taken 

 to select blocks free from shale, or containing but little of it, and that little rather disseminated 

 irregularly through the mass than disposed in layers. 



At Putnam's quarry, the rock is covered with alluvial, being the surface mass, the upper 

 ones having all been swept away ; but at the lower quarry, it is covered by the thin irreg\i- 

 lar layers of Trenton limestone. In both quarries, the birdseye may be seen below this mass, 

 but is very thin. The mass worked is about twelve feet thick, and the sanae layer in some 

 places measures from five to six feet in thickness. Some of the parts of this mass are of a 

 lighter color and more compact character, showing that the cause which gave rise to the mineral 

 nature of the birdseye had not ceased when this mass commenced to form. 



Fossils are not numerous in either quarry ; in which respect it contrasts strongly with the 

 Trenton limestone proper, which rests upon it, and into which, as a limestone, it graduates ; 

 the difference being in the excess of shale in the Trenton portion, and the apparition of fossils 

 not found below it. 



The quarry of Sage and Reed is at the top of the first elevation back of the river. It is 

 the third one on the Mohawk. Its thickness is not so great as the mass at Tripes hill. It is 

 water-worn, showing scratches upon the surface, the direction of which is about east and 



