38 Finch on the Tertiary Formations 
American public, because it shows that for many thousands 
years there is an ample supply of the materials for the 
manufacture of earthenware, porcelain and glass, whenever 
the country shall consider it desirable to support or encour- 
age those manufactures more extensively than at present. 
It is a subject of some interest to ascertain whether the 
fossil shells ef this formation in America are similar to those 
of Europe. At Powleshook, opposite New-York, and at 
the celebrated village of Communipa, on a small elevation 
one quarter of a mile north of it, and to some distance in- 
land, are extensive strata of fossil oyster shells, forming 
beds, from six inches to two feet in thickness. Mr. Pierce, 
in his description of New-Jersey, also mentions many banks 
of them, and I have heard of one which extends several 
miles ; they may probably be classed as belonging to this 
formation. In the opinion of many persons, both learned 
and otherwise, these are shells left by the Indians ; but an 
examination of the places where they occur, especially at 
the hill near Communipa, wlll, | imagine, satisfy every ge- 
ologist as to their origin. — 
sii at ate ris Wied 0 Metlceee: Se ° . Lad pqs 
3. Calcaire Silicieuse, of the Paris basin. 
The siliceous limestone or Buhr stone’ of Georgia, is a 
formation decidedly contemporaneous with the above men- 
tioned stratum; although the principal part of the celebrated 
French mill-stones are froma rock higher in the series, the 
Meuliere sans coquilles, yet some are obtained from the 
Calcaire Grossier ; and to this stratum and the C. Sili- 
cieuse, I consider the Georgia Buhr stone allied, both by 
the similarity of mineralogical character, and the nature of 
fossil remains. The American Buhr stone contains splen- 
did impressions of two or three varieties of mactra. Tel- 
lina, melania and turritella, and many others will no doubt be 
found in it on future investigation. 
- The cavities in the limestone, which are numerous, are 
lined with siliceous incrustations, and if great care was ex- 
ercised in the Georgia quarries to procure only the hardest 
Stratum, it would no doubt supersede the introduction of 
French Buhr stone, but at present they appear to make no 
ion ; consequently many of the softer varieties come 
to market, which are of no use, and prevent their general 
