412 TRANS. OF THE ACAD. OF SCIENCE. 
nishes the white sand so justly celebrated for the manufie 
ture of the purer varieties of glass. Thickness from 30 to 80 
feet. 
The 2d. Magnesian Limestone occupies a large are 
ly in the central and north-western vottiel of the eae 
we draw a line passing south-eastwardly from the sourees 
of the Isle au Bois to a point on Mill Creek, about a ot 
a half above its confluence with the Aux Vases, and thence 
extend this line to the Saline, a short -istanee below ile 
mouth of its North | Fork, et 7 have pretty nearly the 
m the Sanchadola Sandstone; 
west and: south of this line, i ip ranges from one to three 
forming, like the 1st. Magnesian, neatly rounded hills with 
gentle declivities. 
e 2d. anastoné constitutes the edie rock ovgt 
constantly encountered on the high me at ‘the cat 
he Establishment, Terr : ses, : 
find it also occupying the pees of nearly every ‘section 
int. 37, eT. The rock v in lithological charac 
teri different arts of the count, xr usually appears in 
thin beds of Spheee ellow, or reddish colors, and made up 
of ee 
2 y' 
moderately fine silicious grains. Near Cozzens 
Peat of the Aux ases, 3 thickness Ct eee 
met erie mis the ete ee sly ’ 
Saige: ated 
feet above the surface ; some of heated nding quite i nd 
a ie oe eve ight at different ee from a aa 
