OF ARKANSAS. 77 



Immediately overlying this black shale is a black, bituminous limestone, 

 much of the same character as that already mentioned as occurring in the 

 Oil-trough ridge, and occupying very nearly the same geological horizon. 



The section in Wiley's cove is approximately as follows : 



1. Archimedes limestones. 



•2. Eucrinital, and Chonetes limestones, alternating with thin shaly 

 partings. 



3. Black, brittle, bituminous limestone, or marble rock. 



4. Black, bituminous, hard, sheety shale. 



The exact relative thickness of these beds, remains yet to be determined; 

 the two first members are approximately 50 to 60 feet; the third member, 

 some 15 feet ; and the fourth member, from 40 to 60 feet in thickness. 



The superposition in Wiley's cove, renders it highly probable that the 

 black limestone of the Oil-trough ridge, is also underlaid by a black shale, 

 which is concealed, however, beneath the alluvium of White river, the 

 black soil of which is partly derived from it, and, in part, from the wash- 

 ings of the subcarboniferous limestones of the Oil-trough ridge. This is 

 rendered still more probable, from the fact of dark shales and shaly lime- 

 stones occurring under the same black limestones of the subcarboniferous 

 group in Shield's bluff, as may be seen in the section given of that hill, in 

 a previous part of this Report, under the head of " Independence county." 

 In the centre of Wiley's cove, the grey beds of Archimedes limestone lie 

 from 100 to 125 feet above the general level of the farms, and the top of the 

 black shale and base of the black marble at 60 to 70 feet above the same 

 level. 



There is abundance of black chert, strewed in the water-courses of the 

 cove, which approaches very nearly to the character and appearance of 

 the black flints, found in the chalk formation of Europe ; these appear to 

 originate as segregations or concretions in the limestones, overlying the 

 black shales, which, being more difficult of decomposition than their 

 matrix, remain as gravel, while the imbedding rock, itself, has become a 

 part of the rich, black soil of the cove. This is derived, in part, from 

 the subcarboniferous limestone, and, in part, from the black shale. 



The deep mud holes in the road which leads up through the cove, have 

 been washed out of and worked into the tenacious clay, derived from the 

 disintegration of the black slate, and accumulated at the foot of the 

 surrounding hills. 



Haifa mile beyond Wiley's cove, the black slate forms the bed of the 

 Owl or Middle fork of Little Red river, with hard, heavy, dark, ferruginous 



