Geology and Mineralogy of apart of Massachusetts, &c. 21 
7. TRANSITION LIMESTONE. 
Metalliferous Limestone. Eaton.* 
Colored light brown. | 
This Limestone forms a range, about as continuous 
through Rensselaer and Columbia counties, as is the primi- 
tive limestone through Berkshire county. Its extent 
southwards has not keen ascertained; but it continues 
northwards beyond the limit of the section, as Prof. Eaton 
believes, to Lake Champlain.* [tis distinguished by its’ 
somewhat earthy fracture, and its tendency towards the sla- 
ty structure; and is associated to some extent with quartz. 
Though some of it differs but little from the newest primi- 
tive in Berkshire Co., yet its connexion with that which 
possesses the preceding characters has convinced geologists 
that it belongs to the transition series. It is doubtless the 
oldest transition rock in this section of the country. The 
limestone of Hoosack, Petersburgh, Lebanon, Canaan, 
Hillsdale, &c. belongs to this stratum. It occurs in beds 
also still nearer the Hudson. 
‘The mineral spring at New Lebanon is in this rock. 
The latitude of this spring was found by Rittenhouse in 
1787, to be 42° 271) N. The temperature of this spring 
is about 70° Far. 
8. TRANSITION ARGILLITE. 
Colored Carmine. 
This rock lies next west of the transition limestone, and 
joins upon it. It is much less shining than primitive argil- 
lite, and is more full of seams, running in various directions. 
It resembles the argillite along the Hudson. Between the 
two, indeed, lies the gray wacke several miles in width. But 
as strata of argillite occur in the gray wacke near the Hud- 
son, and occasionally farther east, which differ not essen- 
* Geological and Ag. Survey of Rensselaer County. See also Mr. 
Barnes’ Section of the Canaan Mountain, Am. Journ. Vol. V. p. 10, for 
some notices of this rock. 
