ELISHA MITCHELL SCIENTIFIC SOCIETY. ( 



Those residual clays of these regions which have 

 been formed /fi situ are the result of the processes of 

 decay, the operation of which cannot be limited to any 

 definite epoch, but may be ascribed, in g-eneral, to re- 

 cent g-eolog-ic time. 



The most extensive beds of cla\' known in North 

 Carolina are those found in the Coastal Plain reg-ion. 

 In the Potomac (lower Cretaceous; formation, there 

 are extensive beds of laminated, dark-colored cla3's, 

 exposed along- the banks of rivers crossing- the coastal- 

 plain reg-ion, notabh' on the Cape Fear river, for fifty 

 miles below Fayetteville. These clays are usually 

 dark in color, owing- to the vegetable matter which they 

 contain; and, in some cases, the}" are hig-hly lig-nitic. 

 The thin laminae are frequentlv separated by still thin- 

 ner parting's of sand; and frequently within a short 

 distance (from a few feet to a few hundred feet) the 

 clay-laminae become thin and disappear, while the 

 sand-parting's g-radually thicken, so that the whole as- 

 sumes the character of a sand-bed instead of a clay- 

 bed. This feature, which indicates plainly the shift- 

 ing- conditions under which these deposits were laid 

 down in certain localities, illustrated in the accompa- 

 nying- sketch of the river bluff at Prospect Hall on the 

 Cape Fear river, 21J miles below Fa3"etteville. 



In some portions of these clay-beds, pyrite occurs in 

 such quantities as would probabl}' interfere with their 

 industrial use; but the larger portion of the deposits 

 appears to be free from pyrite, and will probabl}' prove 

 to possess considerable economic value. Thus far no 

 efforts have been made to utilize them; but both ana- 

 lytic and practical tests of them are being- made at the 

 present time. 



Along the western border of the Coastal Plain re- 



