182 GEOLOGICAL REPORT. [T303 1 , 303 2 , 304 



This loam (which was instinctively, from its aspect, considered " rich" by the 

 inhabitants), would from its physical, no less than its chemical constitution, 

 form an acceptable addition to any soil ; while the upper strata, which seem to 

 differ from it mainly in the amount of clay which they contain, could be profit- 

 ably employed, where convenient, for the improvement of very light soils. And 

 under similar circumstances, no doubt such materials as those at Monticello, 

 Pope's Ferry, Avera's, etc. (IT 237, 238, 245) would be equally useful. 



303 1 . At Dryer's Perry, S. 11, T. 5, R. 7 W., Jackson county, 

 materials occur which no doubt could be used with great advantage 

 on the poor soils of that region (T246, Sec. 39). They contain 

 large amounts of gypsum, and probably other fertilizing substan- 

 ces — I have not. however, had time to give them a special examin- 

 ation. 



The fertilizers occurring in the formations near the sea-coast, are mentioned in 

 the special description of that region, as well as above (171:24:8,249). 



303' 2 . Gypsum, or Plaster of Paris. — The occurrence of this sub- 

 stance on the territory of the several lignitic stages of the Tertiary, 

 as well as that on the Jackson and Vicksbu; g Groups, has been 

 repeatedly mentioned. It is usually found in crystalline plates, 

 rosettes, or lenticular masses, 1-20 of an inch to 2 inches in thick- 

 ness; but I have not thus far seen it in independent deposits 

 sufficiently large to warrant exploitation of the plaster assiich; 

 although it is very likely that such deposits do exist, and if so, 

 they would be of high value in agriculture. In most cases, the 

 mineral is intermixed in small crystals or thin sheets, with clayey 

 materials, so as to be available only in connection with these; 

 forming gypseous marls, whose agricultural value is only thus far 

 inferior to that of pure plaster, as they will not bear transporta- 

 tion so well. Some of them, however, undoubtedly contain other 

 valuable ingredients besides gypsum, and it is possible that not a 

 few of the lignito-gypseous materials found in S. Carroll, Attala, 

 Leake, Holmes and N. Madison (180, 183, 187), as well as in 

 Hinds, Rankin and Scott, will prove valuable fertilizers. 



I have not, however, thus far given as much attention to their investigation as 

 to that of the more generally important " calcareous " marls, and greensands; an 

 analysis of one of them will be found in the Agricultural Report, under the 

 head of the "Central Prairie Region," whose gypseous prairies owe their exist- 

 ence to the gypseous clay marls. Other data concerning their occurrence are 

 given in ir IT 215 to 219, 231, 233, 241, 246. The largest masses of pure gypsum 

 on selenite, of whose occurrence I am aware, have been found in wells near Cato, 

 Rankin county (H241 — a ledge from ten to twelve inches thick); in the railroad 

 cut near Clinton (crystalline masses one to two inches thick and of a square-foot 

 surface); on the gypseous prairies of W. Hinds (Wailes); in Dr. Galloway's 

 well, near Kosciusko (187), and on the Pelahatchie near Mr. J. Parker's (125). 



304. Limestones of the Marine Tertiary.— Limestonessuitable 

 for lime-burning, as well as for building purposes, are chiefly found 

 on the territory of the Yicksburg Group. The limestones, or 

 rather, indurate marls occasionally found within the two other 

 groups, are generally too soft for building purposes, and not nearly 

 as pure as the hard blue limestones of the Vicksburg Group. 



The only locality known to me on the territory of the Claiborne Group, where 



