166 Tertiary. 



mouth of the Matan the clay and gravel banks are upward of SO feet 

 high. 



Robert W. Gibbes* described^, froni the Eocene of South Carolina, 

 Pristis agassizi. 



In 1848, M. Tuoine^t said that the Tertiar}- rocks of South Caro- 

 lina are composed of beds of loose sand, claj, gravel and sandstone, 

 together with strata of limestone, of great thickness, and beds of soft or 

 pulverulent marl. 



A line drawn from the mouth of Stevens' creek, on the Savannah, 

 north of Hamburg, crossing the Saluda and Broad rivers, near their 

 junction; the Wateree, at the canal; Lj-nch's creek at Evan's Ferry; 

 and Thompson's creek, at the point where it enters the State, in Ches- 

 terfield district, will approximately mark the northern boundaiy. 

 Wherever the rivers, in their downward course, enter this boundary' , they 

 wash away the more yielding Tertiary rocks, and expose the meta- 

 morphic, and very frequently the granitic rocks; and hence it is, that, 

 at these points, In ascending the rivers, we meet with the first falls. 



The Eocene, in South Carolina, has a thickness of 1,000 or 1,100 teet, 

 and consists of three well-defined groups. 1. The Buhr-stcne group, 

 composed of thick beds of sand, gravel, grit, clay and buhr-stone, 

 amounting to at least 400 feet in thickness, and undcrl3'ing the calca- 

 reous beds. Its upper portions are characterized by beds abounding 

 , in silicified shells, for the most part identical with the Claiborne fos- 

 sils. As these are littoral shells, the3^ probably occupied the coast, 

 while the Santee beds were forming in deep water. The materials of 

 which this group is composed are the ruins of the granitic and meta- 

 morphic rocks of the upper districts. Good exposures occur at the ferry 

 below Augusta, in the high red cliffs overlooking the town of Ham- 

 burg, between Aikin and Graniteville, on Horse creek and Cedar creek, 

 and at the head of Congaree creek. It ma}- be traced from Barnwell 

 to Sumter, a distance of 100 miles, and it occurs on Huspa creek, in 

 Beaufort district, and at many other places. 



2. The Santee beds, consisting of thick beds of white limestone, 

 marl and green sand. These are best seen on the. Santee, where, in- 

 terstratified with the green sand, they dip gently toward the south. 

 The coralline marl of Eutaw is found near the upper edge of these 

 beds. The irregular area occupied by these becls, is about 75 miles 

 lono- and 60 miles wide. 



* .Jour. Acad. Nat. Sci., 2fl ser., vol. i. 

 t Tuomey Rep. Geo. of South Carolina. 



