150 GEOLOGY OF THE SECOND DISTRICT. 



CHAPTER IX. 



Individual rocks composing the Taconic system ; their characters ; absence of fossils. — 



Mineral products. — Conclusion. 



The order in which the Taconic rocks lie being unsettled, or at least not being so clearly 

 established as is desirable, I am not particularly anxious to follow the usual order in the 

 description of the individual masses composing this system. I shall therefore commence with 

 the most western mass of slate, which I have denominated Taconic slate. 



This rock is extremely fine grained, with delicate inelastic lamina;, and only slightly cohe- 

 rent ; or in other words, the laminae are separated easily from each other, especially where 

 the rock is near the surface. The color is dark, passing into light blue, and often stained 

 brown by decomposed sulphuret of iron. Small masses of quartz arc often enclosed between 

 the lamina; of slate. A waved or slightly wrinkled state of the lamina; is commonly exhibited, 

 attended with a pearly lustre, and often with a reddish brown color. No organic remains 

 have, however, been found in the rock ; it is even destitute of those obscure markings which 

 arc c&\\c<\. fucoids. Although then it has a general resemblance to the magnesian slate, which 

 forms the greatest part if not the whole of the Taconic mountain, it is not so coarse, contains 

 less quartz, and rarely if any chlorite. It is not, however, possible to describe this mass 

 with sufficient precision to identify it without regard to its position. It may be said to lie 

 between the Hudson river rocks on the west, and the sparry limestone on the east : it is un- 

 doubtedly overlapped by the former rocks, and it passes beneath the latter under a dip of 30° 

 or 35°. The line of junction with the slates upon the west is exceedingly obscure, and I am 

 not aware that it has been observed. On the east, however, the junction of the slate with 

 the limestone is clear and distinct. It may be observed two or three miles east of Hoosic 

 corners, on the Bennington road, near the hcmatitic ore bed. The layers of the slate and 

 limestone alternate several times with each other, before the limestone finally prevails. I 

 have not been able to make even an approximate estimate of the thickness of this slate : 

 towards the western edge, the rock is concealed beneath debris of stones and soil. 



This rock holds a definite position in the series, and may be traced very clearly for one 

 hiuidred and fifty to two hundred miles, without any variation of character. Its strike varies 

 but little from a north and south course, and may be traced by drawing lines near to, and 

 parallel wiili the New- York State line upon the east. The rock, immediately upon its 



