312 



VEINS IN SLATE. 



The sparry limestone at St. Albans Bay, and many other limestones further south, 

 belong to this group. It is not confined to the so-called Taconic rocks. 



FIG. 387. 



Veins in Slate, Butler's bland. 



In the northern part of the State the beds of limestone in the Hudson River Group are 

 sometimes dolomitic, or more often pure carbonate of lime. Fig. 228 shows the position 

 of the various limestones and slates at Highgate Falls. It is altered from a wood cut in 

 the Geology of the Second District of New York, p. 321. 



FIG. 228. 



Hudson River Group, 



Gray grit. 



3 4 8 8 7 



Section at Highgate Falls. 



10 



Explanation of Fig. 228. 



1 Drab-colored, even-bedded layers. 



2 Slate filled with imperfect concretions. 



3 Drab-colored layers, similar to strata in the calciferous sandrock. 



4 Drab-colored limestone, with a few fossils. 



5 Even-bedded slate. 



6 Slaty limestone. 



7 Dove-colored limestone like the Swanton marble. 



8 Slaty limestone. 



9 Fragmentary limestone. 



10 Masses of shale and grit, alternating regularly with each other, belonging to the Red Sandrock Series. 



There is a considerable fall in the Missisco River at this locality, and a deep gorge has 

 been worn through the rocks, so that their nature is distinctly seen. The section above 

 is embraced in the space of fifty yards, and the height of the cliffs is generally more than 

 fifty feet. The dove-colored limestones in general correspond lithologically to the belt of 

 limestone a few miles' west, as at Swanton Falls. It is a pure limestone traversed, or 

 rather reticulated by veins of calcite. The stratification is very obscure, and the rock 

 breaks naturally into irregular angular fragments. 



