1295 2 , 296, 297J marls ok the grand gulp group. 177 



latter, under the head of the Central Prairie Region, a? well as 

 below (T303 2 ). 



295-. Calcareous Marls of the Fresh- Water Tertiary of South 

 Mississippi, or Southern Lignitic. — Calcareous marls, void of shells, 

 and very claye}-, occur in limited patches on the territory of the 

 Grand Gulf Group. These deposits are local phenomena — the 

 strata containing them either run out beyond a limited space, or 

 more generally, the material changes its character- loses its calca- 

 reous constituent, and becomes a simple gray clay, it is not pos- 

 sible therefore to trace out such deposits from place to place, as we 

 have done in describing the marls of the marine Tertiary : they 

 turn up occasionally, any where on the territory of the Grand Gulf 

 Group. 



At Grand Gulf, as the section shows, (Section 33, 1f232), we have calca- 

 reous clays at two different levels, in strata Nos. 1 and 8 ; the latter especially, 

 in some portions of the bed, would no doubt make an effectual manure. But 

 it is not to be traced at other points of the outcrop, and the same is the case 

 with No. 1, which is visible as such only at the lower end of the bluff The 

 material might form a good dressing for light soils, buts its quality would not 

 entitle it to more than local importance. The amount of lime contained in the 

 mass may be judged of by the eye, since it forms whitish specks in a gree» 

 mass. 



296. The only other deposit of this character and of any impor- 

 tance, which I know of, W. of Pearl River, is a bed of brown clay 

 marl occurring at Judge Hiram Cassedy's, S. 1 T. 6, R. 3 E., on 

 the hills bordering on the S., the S. fork of the Homochitto, in 

 Franklin county. 



It forms a " prairie" spot on a hilltop, about an acre in extent, and consists of 

 a stratum some 8 feet in thickness, of a stiff, dark orange-colored clay, inter- 

 spersed with specks of white, limy concretions, which are largest and most 

 abundant in the lower portion (the lowest 3 feet) of the deposit, where they 

 occur of the size of a hen's egg, and sometimes larger. The whole of the clayey 

 mass, howcr, efforvesces with acids. The spot bears the usual evidence of a 

 calcareous soil in its vegetation, which consists chiefly of Crab- Apple and a 

 species of Red Haw (or Hawthorn), and on its outskirts, where the soil is not 

 excessively heavy, Wild Plum and Honey Locust also ; while the other timber 

 is thin and much stunted. The whole was probably once covered with dark 

 eolored prairie soil, which is now found only in patches ; and it is stated that 

 when the country was first settled, the spot was entirely overgrown witk 

 strawberry bushes. 



297. The specimen analyzed represents about the average (exclusivo of the 

 large lumps of lime) of the lowest four feet. It is a hard, reddish-brown clay, 

 with numerous white specks and veins. 



R— 12 



