No. 200. J 
167 
(lium at which they are fixed, give it a Very fine effect. This is parti- 
cularly true in large slabs, which present a great diversity of appearance, 
and could scarcely be distinguished from the similar transition marble of 
the Peak of Derbyshire, which it greatly resembles, and quite equals in 
beauty and firmness." — [Silliman's Journal^ VI. p. 371.] 
Inierstratified Limestones ^ Compact, Sparry and Brecciaied, 
The next series of limestones is interstratified with the slate rocks, 
which form a large part of Columbia and Dutchess counties. These 
limestones are argillaceous, fissile, and interlaminated with the slate in 
some places; at others it forms beds of twenty to fifty feet thick of solid 
blue compact limestone, checquered by narrow veins of calc spar, tra- 
versing it in various directions; in other places it is a conglomerate, 
formed of rounded or of angular masses, cemented by an argillaceous or 
calcareous matter, which varies according to the nature of the contigu- 
ous rocks. 
No fossil remains have been observed in these limestones, except a 
few which occur in a thin layer of this rock interstratified with slate, 
about one and a quarter miles above Barnegat, on the shore of the Hud- 
son river. 
The limestone beds which are traversed by veins of calc spar, have 
been very justly named, by Prof. Eaton, sparry or checquered limestone; 
names which, in many localities are descriptive, and involve no theore- 
tical considerations. This rock, as well as the conglomerate limestones 
of the Hudson valley, will probably afford valuable quarries of ornamen- 
tal marble. 
Very numerous localities of these rocks were seen; a few only of the 
most important will be mentioned. The black and sparry black lime- 
stone abound at Rider's mills, in Chatham, (where they are frequently 
glazed with anthracite,) also at Maiden; on the east side of Kinder- 
hook lake; between North Chatham and Maiden; and near Canaan Cen- 
tre. 
The conglomerate limestone is seen at great advantage at the stone 
quarries in the north part of Stuyvesant, on the banks of the Hudson, 
and for a mile south it forms the upper layer of the bank of the river. 
At Great Nutten Hook it is interstratified with slate and limestone, and 
sandstone, which are also interstratified in this group of slates. It may 
be seen also two and a half miles southwest of Hudson, on the road to 
Oak Hill ferry; in a ridge of hills northwest of Johnstown, about four 
