232 AGRICULTURAL REPORT. [*i450, 451, 452, 45$ 



of potash, owing to grains of greensand scattered through the mass. Such are 

 the marls at Ruckersville, at Braddock's, at Ripley, and at Col. M. Berry's ; also 

 on Dry Creek, and on the E. fork of the Hatchie, in Tippah ; those cropping out 

 on the banks of King's Creek, Okonatyhatchie, and on the western slope of the 

 Pontotoc Ridge generally, down to its termination in Chickasaw county, between 

 the heads of the Houlka and Chuckatonche (H 144). Near their western limit, 

 skirting the Flatwoods, they are often associated with (usually overlaid by) 

 ledges of sandy limestone, which at times appeal's compact and solid, and then 

 furnishes good lime for building purposes (If 151) ; at others, being unequally 

 impregnated with lime in its different portions, assumes the character of "bored" 

 or "horsebone" limestone. Like the marls, this limestone is often very rich in 

 greensand grains (if 153). It is a soft variety of this limestone, frequently 

 associated with a heavy, gray, clay marl, which forms the bald hilltops on the 

 Pontotoc Ridge. 



450. c. Clay mads of the Rotten Limestone character and age, (lfl41) ; 

 passing into the Rotten Limestone hy insensible gradations, and containing from 

 20 to 85 percent, of carbonate of lime. Their admixture consists prevalently 

 of clay, instead of sand, as in those before described. 



On an average they are poorer in potash than the greensand marls, although 

 the Houston marl still contains near % of a per cent (if 141) ; while the 

 Okalona Rotten Limestone contains only one quarter of a per cent. (11149). 

 The marls of Tishomingo and western Itawamba (at Richmond, and on Old 

 Town Creek) ; and that of Chiwapa, Coonewaand Tallabinela Creeks, in eastern 

 Pontotoc, belong to this class. 



451. c. Greenish sands, very micaceous, of the lower Rotten Limestone (or 

 Tombigbee Sand) age (if 140), occurring in Monroe and Lowndes counties, on 

 the Tombigbee and some of its western tributaries. Thus at Aberdeen (if 113), 

 Barton (if 107), Waverley, Plymouth Bluff, and Columbus (if 114).— Of these 

 materials, only one specimen has as yet been analyzed, viz : that from Waverley 

 Bluff, which gives only between two and three per cent, of carbonate of lime, 

 and a very small amount of potash (if 140) ; so that its use as a manure would 

 hardly pay for the hauling. The material occurring at Plymouth and Barton 

 Bluffs, however, is evidently richer in lime, and may prove valuable. 



452. II. Marine t3rtiary marls, occupying a belt extending across the State in a 

 W. N. W. direction, from the Mississippi, at Vicksburg, to the Alabama line ; 

 represented, on the map, by the several shades of blue, and bluish-gray. These 

 marls are scarcely less various in their character than those of the cretaceous 

 formation, to which they bear a great general resemblance. The tertiary 

 greensand marls are on the whole distinguishable at once by the want of mica, 

 from those of a similar general aspect derived from the northeastern or cretaceous 

 marl region ; while the white tertiary marls, corresponding in aspect to the 

 Rotten Limestone, are distinguished by their granular or crystalline texture, 

 and their yellowish (instead of bluish) tint when freshly dug. 



They are on an average richer in lime and potash than those of the first class, 

 containing from 50 to 95 per cent, of carbonate of lime, from ?{ to 1% (as far as 

 known) per cent, of potash, from 1 to 3 per cent, of magnesia, and % to % per 

 cent, of phosphoric acid. 



453. Qreensand marls occur more or less in all of the three stages of the 

 marine Tertiary (see Geological Report, 1f277). 



Almost always, however, they are accompanied by the white marls, and cannot 

 therefore be as distinctly circumscribed in their limits as in the case of the 

 cretaceous formation. They are generally rather sandy, as compared with the 

 white marls ; some of which, as those of Madison and N. Hinds counties, are 

 very clayey, with but a slight admixture of sand ; in other cases (as near 

 Brandon, 1f285 ; in S. Jasper, and N. Wayne, 1f294), are almost entirely 

 composed of granular carbonate of lime, often passing imperceptibly into hard 

 limestone ; and at other times, as imperceptibly into greensand marls, e. g. at. 



