38 Finch on the Tertiary Formations 



American public, because it shows that for many thousands 

 of 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 supporter 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, will, I imagine, satisfy every ge- 

 ologist as to their origin. 



3. Calcaire Silicievse, of the Paris basin. 



The siliceous limestone or Buhr stone of Georgia, is a 

 fbrmation decidedly contemporaneous with the above men- 

 tioned stratum; although the principal part of the celebrated 

 French mill-stones are from a 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 

 selection ; consequently many of the softer varieties come 

 to market, which are of no «se, and prevent their general 



