1*109] TOMBIGBEB SAND GROUP. 60 



surface and heavy soils ; while towards the territory of the 

 Eutaw Group little difference is noticable, beyond that in the well 

 waters. 



The prevalent and characteristic material of this Group, as has 

 been stated, is a fine-grained micaceous sand, more or lees calca- 

 reous, usually of a greenish tint, but not unfrequently gray, bluish, 

 black, yellowish and sometimes even orange red. Clays and non- 

 calcareous (as also at times non-micaceous) sands are also found, 

 although generally they are only subordinate to the characteristic 

 greenish sand, which is the exclusive material in the southerly 

 region of development, in S. Monroe, and Lowndes. In N. Tisho- 

 mingo, there is a considerable variety of materials, among which 

 bluish black clayey sands or sandy clays, and sands variegated 

 with blue and yellow (frequently non-effervescent, but always 

 strongly micaceous) are prominent. In S. Tishomingo,. however, 

 on the waters of Big Brown's Creek, the materials are undietinr 

 guishable from those prevailing in Lowndes county, like which 

 they contain indurate ledges at short intervals. 



Near to the edge of the Rotten Limestone, however, and partic- 

 ularly where they immediately underlie the latter, these sands arc 

 mostly loose and water-bearing, and light colored. In Itawamba, 

 outcrops of their strata are scarce, their presence being recognized 

 chiefly in wells ; from Aberdeen down to several miles below 

 Columbus, however, it forms the main mass of the river bluffs. 



The greenish tint is imparted to these sands not by greensand grains, as is the 

 case in the marls of the Ripley Group, but is caused by a greenish incrustation '" 

 covering thinly a portion of the quartz grains. Whether or not this incrusta- 

 tion is of a glauconitic nature, I hive thus far been unable to determine. ' 



109. Beginning at the north, in T. 1, R. 9 E., Tishomingo county, we occa- 

 sionally find in the (dug) wells a black, fetid, micaceous, non-effervescent clayey 

 sand, while natural outcrops scarcely occur; the same is the case in T. 2, R. 

 9 E., and the adjoining portions of T. 2, R. 8 E. — a hilly, sandy region, thinly 

 settled, except along the water courses ; the surface of which is covered with 

 Orange Sand strata, beneath which, at depths varying from 4 to 20 feet, th« 

 cretaceous strata are struck. It is in this region particularly that the denudft- ' 

 tion which the latter have experienced, previous to the deposition of thepresenl 

 surface materials, becomes very apparent, from the fact that the dark colored " 

 sands are struck at the same average depth on the hilltops as on the hillsides. : 

 This condition of things is abundantly illustrated in the R. R. cuts oi the region, 

 a section of one of which, on Harris' contract, S. 3, T. 3, R. 9 E., has been : 

 given in connection with the Orange Sand formation (1f39, Diagram No. 2). 



