72 Review of M. Tuomeifs Final Report 



R 



as 



results of his investigations in the tertiary deposits. 



" 1st. That they are situated in a vast depression in the creta- 

 ceous rocks, which however are only visible on the east and 



northeast. 



"2d. That the eocene consists of three well defined groups: 

 1. The burr-stone formation, composed of thick beds of sand, 

 gravel, grit, clay, and burr-stone, amounting to at least 400 feet 

 in thickness — and underlying the calcareous beds. Its upper por- 



tions are characterized by beds abounding in silicified shells, for 



the most part identical with the Claiborne fossils. As these are 

 littoral shells, they probably occupied the coast while the San tee 

 beds were forming in deep water. The materials of which this 

 formation is composed, are the ruins of the granitic and meta- 

 morphic rocks of the upper districts, which may often be traced 

 to their origin. 2. The Santee beds, consisting of thick beds of 

 white limestone, marl and green sand. These are best seen on the 



Santee where, interstratified with the green sand, they dip gently 



towards the south. The coralline marl of Eutaw is found near 

 the upper edge of these beds. 3. The Ashley and Cooper beds, 

 which are the newest eocene beds of the state. The marl of 

 these is characterized by its dark grey color and granular texture, 

 while the remains of fishes and mammalia give its fossil remains 

 a peculiar character, and leave no doubt of the position assigned 

 it, at the top of the eocene series. These together with the 

 Santee beds, must amount, at least to a thickness of six or seven 

 hundred feet. 



" 3d. That although these strata contain, throughout, charac- 

 teristic eocene fossils, yet they also enclose some cretaceous forms. 



" 4th. That the middle tertiary of the state, composed of beds 

 of sand and marl, highly fossiliferous, is scattered, like similar 

 beds in other places, over the eocene and cretaceous formations, 

 in isolated patches. That the proportion of recent species in- 

 creases towards the south ; and that the extinction of species 

 seems to proceed in that direction, as is proved by the fact that 

 the recent forms, which are also fossil, belong to a more southern 

 fauna — there being but one or two exceptions. 



" 5th. That in South Carolina, the proportion of recent spe- 

 cies in this formation amounts to forty per cent. I have therefore 

 referred it to the older pliocene. 



11 6th. That the post-pliocene is confined to a belt along the 

 coast of about eight or nine miles in breadth. The fossils are 

 nearly all referable to recent species now inhabiting the coast : a 

 few, however, belong to the fauna of Florida and the West In- 

 dies. An elevation of the coast has taken place since the deposi- 

 tion of these beds, which it is probable has given the rivers of 

 the Atlantic slope a western tendency. 



