1337, 338, 339, 340J flatwoods soils — brick clays. 199 



usually to the extent of 2 to 3 per cent. These concretions are of a concentric 

 structure, consisting of thin, variously colored layers of hydrated peroxide of iron ; 

 they are sometimes hollow and filled with a soft, olive-green ferruginous mass 

 (phosphate ?). Similar concretions occur in the yellow loam subsoils of the 

 hills, wherever a calcareous formation underlies ; as in the case on the Pontotoc 

 Ridge, and especially in the Tippah (and Chickasaw) "Buncombes," where these 

 concretions are so numerous and acquire so large a size (e. g that of a fist, with 

 a weight of several pounds) as to be somewhat of an obstruction in tillage. 

 Most of the "lied Lands" of the Pontotoc Ridge (1T129) contain these concre- 

 tions, of about the same size and frequency of occurrence, as the prairie soils. 



337. The great rcsistence which, on account of their clayey character, the 

 soil and subsoil of the prairies oppose to washing or denudation, readily accounts 

 for the levelness of the prairie region, which, immediately after the deposition of 

 the loam, it probably shared with the immediately adjoining country, with 

 whose hilltops it is now generally on a level. The subsequent denudations, 

 which wore deep gullies and valleys into the surface occupied by light, sandy 

 materials, would leave the heavy surface deposits of the prairie (derived mainly 

 from the clay marls of the underlying formation) comparatively untouched. 



The heavy soil of the Flatwoods («[[16i,165) may, in part, have been formed 

 in a manner similar to the prairie soil. It appears as though in the case of the 

 Flatwoods as well as the prairies, the impervious material, which yielded but 

 slightly to denudation, had prevented the deposition, or favored the subsequent 

 removal, of the Orange SanJ, so that in both cases, the materials of the more 

 ancient formations themselves essentially have formed the soil. The formation 

 of the Flatwoods soil out of the heavy gray clays of the Lignitic, is constantly 

 in progress, wherever the latter is near enough to the surface to be reached by 

 the action of the atmosphere ; but strata 10 to 20 feet in thickness could hardly 

 have been thus produced. 



The light Flatwoods soil (see Agricultural Report), however, is evidently of a 

 later formation than the red loam, by which it is frequently underlaid ; and 

 both this fact, and its peculiar character, seem to place it within the period of 

 the formation of the Second Bottoms (see below, 1f340). 



338. While on a large part of the territory of the calcareous formations, the 

 smooth, round pebbles of brown iron ore characterize the loam, we often find, 

 elsewhere, a part of the iron contained in the loam, secreted in the form of Bog 

 Ore (commonly called "black pebble"), whose concretions possess no definite 

 form, nor, indeed, are always distinctly separable from the surrounding loam ; 

 into which, from the dark-brown nucleus, there are many shades of transition. 

 Where these black pebbles appear on the uplands, in the absence of any obvious 

 defect of drainage, they are generally considered a sign of an inferior soil (as in 

 some portions of Rankin, and in S. W. Winston counties;) but the best soils of 

 the Yellow Loam character will secrete their iron in this manner, and become 

 white in their mass, when the drainage is insufficient ; and hence, bog iron ore, 

 though most common in the soils and subsoils of the bottoms and second 

 bottoms, occasionally occurs even in the best upland soils. 



339. The loam of the hillsides, which has been removed from its original 

 position on the ridges, differs in no essential particular from the original material, 

 except where either denudation has progressed so far as to penetrate into the 

 Orange Sand, or else, where the washings of high Orange Sand ridges, not 

 originally covered with loam, mixed with the latter when washed down the 

 hillsides. The soils thus produced are, of course, lighter than those derived from 

 the loam alone, and resemble the Hommock or Second Bottom soils, the main 

 mass of which, formed at a period subsequent to the deposition of the loam, 

 seems toconstitute the formation immediately preceding our present era. 



340- Uses of the Yellow Loam. — Its most important office, 

 unquestionably, is that of forming the best upland soils and subsoils 



