174 



PROCEEDINGS OF 



Alabama, and is, perhaps, the most unvarying and curious in shape, and cer- 

 tainly one of the most easily recognised of the irregular forms of this difficult 

 genus. It has a most important claim to the attention of the speculative geologist, 

 for, like the litkodomus marks on the pillars of the temple of Serapis, I conceive 

 that it affords evidence of a rising above and sinking beneath the level of the sea, 

 of the lower tertiary beds of Alabama. Wherever we find a continuous deposit of 

 fossil oyster-shells, we recognise an ancient estuary, bay, or lagoon, cut off from 

 the main ocean ; for in no geological period were these bivalves ever colonized ia 

 the open sea, although they were liable to have been occasionally drifted there by 

 currents. To present a clear view of the subject, I subjoin a section of the cliff at 

 Claiborne, with a description, originally published in the Journal of the Academy 

 of Natural Sciences of Philadelphia, in lb34, and in my work on tertiary fossils, in 

 1835. The section is in the ascending order. 



45 feet. 



3 feet. 



17 feet. 



3 feet. 



70 feet. 



Level of the Alabama river, in the lowest stage of the water. 



1. The inferior stratum is a dark-colored mixture of sand and clay, containing 

 a group of shells, many of the species of which occur in the arenaceous deposit. 

 No. 3 of the section. 



2. A dark-colored clay or marl, seventy feet in thickness, charactciized by On- 

 trea selWfonnis, generally of a small size, with disunited valves, and rather sparsely 



ated with a diRercnt group of fossils from any I had observed in Alabama. In Dr. Morton's " Synopsis of 

 the Organic Kenuins of the Creucuons Group,"' the white linu:stone,in which this oyster shell occurs, 

 ■was referred to the upper division of this group; hut further inresligatiuii of the fossils has satislied 

 mc that they are of eocene origin. Two species of organic reinaiua which occur in the limestone, (Scu- 

 telln Lyetli and Pi-cli-n cahatus^ I have obtained from the newest stratum at Claiborne, No. 4 of the 

 section ; but this Carolina limestone I believe to have l>een depositeil in estuaries, like stratum No. 2, of 

 the Claiborne section, with which it is doubtless of precisely the »ame geological age. Dr. Illanding, 

 many years since, presented nit sp<'einiens of Oilriu tcHaformit anil CnrilUa lUanitingi, whiili he found 

 >t Vance's fcrry» on the Santce river, anil which enableil me to connect the formation of that locality 

 with the eocene of Alabama. The following is a list of the fossils which I found in 1832, in the dilTenni 

 localities of lower tertiary limestone in South-Carolina: Conus gyratus, Olivia carolinensis, Cypni-a 

 lapido<a, Ostrea sellr-formis, Prcien cals-atus, P. memhranosui, Tenebratula laehrj-ma, llalanus pert- 

 rrinus. Scitella Lvrlli, Lunulitci l.yellisl.. catolincnsu, F.chinus infulntus, Anthophyllum cuneirocnrii 



