40 Finch on the Tertiart/ Formations 



In works upon Geology, when noticing the extent of 

 banks of fossil shells which are known to be abundant in 

 various parts of the world, that near Tours in France, has 

 generally been considered as most extensive. It is a bank 

 of shells nearly unchanged, nine leagues long and twenty 

 feet thick, but in the Southern States of America the stra- 

 tum of shells, which is now to be described, extends six 

 hundred miles in length, from ten to one hundred miles 

 in width, and if the known measurement in one part of the 

 line may be supposed a fair criterion, three hundred feet in 

 thickness. The principal part of the formation is composed 

 of shells, and therefore may be hereafter classed as the lar- 

 gest collection of fossils in the world. 



All my information respecting it is derived from Nath'l. 

 A. Ware, Esq member of the Academy of Natural Scien- 

 ces, Philadelphia, who travelled over many parts of this 

 formation, and paid great attention to its character. In 

 Bartram's travels to the Southern States, the commence- 

 ment of this stratum is mentioned, and the termination of it 

 in the Chickasaw country is noticed by a writer in Silliman's 

 Journal ; but this is the first memoir which traces it through 

 its whole extent, and the public are sojely indebted to Ma- 

 jor Ware for the account. 



Character. It is a stratum of shells, in some situations 

 united by a scanty calcareous ceroent, but from which the 

 shells may be readily detached; in this state it is called by 

 the inhabitants a soft limestone, which in the quarry is ea- 

 sily cut by any edge tools, but becomes harder on exposure 

 to the air. In other parts it presents immense banks of 

 loose shells, ten or fifteen miles in length, without the mix- 

 ture of any foreign substance. 



Fossils. This extensive formation is chiefly composed 

 of a large species of ostrea, which I believe has not yet 

 been described. A specimen of it may be seen in the Phil- 

 adelphia museum ; it is twelve inches long and two and 

 three-quarters wide, and each valve from half to two and 

 a quarter inches thick — Major Ware says they occur larger ; 

 on account of their great size I propose to call them Ostrea 

 Gigantissima. The shells appear but slightly changed by 

 their residence in the earth, and are in many parts used for 

 burning into lime. 



