40 FOURTH REPORT — 1834. 



some fifteen or twenty feet. This would appear to be the pre- 

 vailing order, not only in all the portion of Virginia here de- 

 scribed but throughout the middle tertiary region, from whatever 

 part of it accounts have reached us, whether from Maryland or 

 North Carolina. 



North Carol hw. — The middle tertiary beds are prolonged 

 through this State in a belt, the east and west boundaries of 

 which are not at present ascertained, but which appears to con- 

 tract both in width and thickness as we proceed south. 



Professor Mitchell, of the University of North Carolina, men- 

 tions it as ranging through the following localities : Near the 

 northern boundary of the State it appears on the Meherrin river 

 at Murfreesboro' ; further south, on the banks of the Roanoke at 

 Scotland Neck ; again on the banks of Fishing Creek near In- 

 field, in Halifax county, and on the banks of the Tar river near 

 Greenville, in Pitt countj^, and also a little below the falls of the 

 Tar ; in several places in Craven county, and on the banks of the 

 Neuse, below Newbern. It appears also in Duplin comity, and 

 on the banks of Cape Fear river, at Walker's Bluffs, and eight 

 miles above Elizabeth. Walker's Bluff, like all the other con- 

 siderable bluffs in this State, is on the western or right bank of 

 the river as we descend. It extends about three fourths of a mile 

 along the river, and then recedes and loses itself in the general 

 plain of the country above. The stratum of shells is from five 

 to twelve or fifteen feet in thickness, and its upper surface 

 seventy-five feet above the mean level of the water in the river. 

 The tide flows a few miles above it. Beneath the shells are al- 

 ternating and irregular strata of sand and blue tenacious clay, 

 the latter predominating. Above the shells the surface rises as 

 we recede from the river, until it gains a height of about one 

 hundred feet, which is not far from the average level of the sur- 

 face of this portion of the State above the sea. In Duplin and 

 many parts of the south-eastern corner of the State, as along 

 Cape Fear River, near Wilmington, this formation rests imme- 

 diately upon the upper zoophitic limestone of our southern cre- 

 taceous rocks. It is here in fact a mere capping, having a 

 thickness of not more than a very few feet, but still abounding 

 in characteristic fossils. 



South Carolina. — Mr. Conrad has the following observation 

 in allusion to the southern extremity of these beds, which I have 

 here termed middle tertiary : " The formation has not been 

 found south of Vances Ferry, on the Santee river, in South 

 Carolina ; nor do I believe it occurs in Georgia, Alabama, or 

 Mississippi. I never myself observed it in any part of Soutli 

 Carolina, though I explored the country between Charleston and 



