234, & 5'. 2H5' J , li#»»| i;i;.iMi GULF SANDSTONE. I 



iU; half of the bulk of the rock, li is not of conn 

 rence, except aear the latitude of Grand Gulf. It appeal >ut 15 



inches thick, on hillsides at a branch about 2 miles S W. of Port Gibso.n, 

 underlaid by massy blue clay ; an outcrop N. oi Tort Gibson, on Mr. J. C. 

 Humphreys' hind, does not exhibit the peculiar structure of the "Grand Gulf 

 rock.-" At Rocky Spring, in a profil t, we Bnd only 2 or 3 feet < f the 



peculiar rock, and then rather in lenticular masses than in continuous 

 the rest beiqg soft sandstones, clays, etc., which form the usual material of the 

 numerous outcrops in Claiborne and S. Hinds;: would he 



endless repetition, the only rule being, that nenr to the edge of the calcareous 

 fiVicksburg) strata, the materials irly those of the 



lignite: mation near Brandon (H"218 ff.) There are, however, in 



several localities, strata of considerable thickness, of solid sandstone, hard 

 enough to answer for architectural purposes ; thus at the Grindstone Ford, 

 where the Raymond and Port Gibson road crosses the Bayou Pierre, a solid 

 stratum at least 15 feet in thickness, crops out on the blu'l, and similar ledges 

 occur near the Mississippi Springs ; the rock being, however, ordinary siliceous 

 sandstone. Between Terry and Crystal Springs, ledges of white sandstone are 

 exhibited in several cuts — generally soft, and alternating with materials still 

 softer; the true " Grand Gulf rock" is found there also, however, it is said to 

 be very abundant in the heads of the Bayou Pierre in Copiah county generally. 



234 Silicified wood is very abundant in S. Hinds and E. Claiborne, as well as 

 in Copiah ; trunks of trees with roots still visible, are said to occur S. of Rocky 

 Spring. It is in this region, on the Bayou Pierre, that silicified palm wood is 

 often found ; numerous specimens of it have been picked up near Rocky Spring. 

 It also occurs, however, in Hinds county ; a very fine specimen, found near 

 Spring Ridge P. 0., h is lately been presented by Dr. W. Thompson ; and in 

 Mrs. Oakley's collection, at Jackson, there are specimens found by Governor 

 Matthews in the bank of Pearl River, close to the town. 



Beds of lignite appear to occur in several localities, near Big Black River, W . 

 and N. W. of Rocky Spring. One 2 feet thick is mentioned by Prof. Wailes, as 

 being inclosed between two ledges of sanlstone, and impressions of aquatic- 

 plants are mentioned as occurring in it. Another is said to have been struck in 

 a well on S. 11, T. 4, R. 3 W., Hinds county, at thirty-five feet ; and another 

 still is mentioned as existing on Pearl River at Partin's Ferry, Hinds county. 



235 1 In Jefferson county the materials of the formation appear to be generally 

 soft (or at least brittle) sandstones, and clays. The strata underlying the town 

 of Fayette, which crop out a short distance from the place, on the Port Gibson 

 road, seem to correspond to strata No's 3, 4 & 5 of the Grand Gulf profile ; the 

 fine grained, dark gray, brittle sandstone, on the exposed surfaces of which 

 efflorescences of salts occasionally appear, is sometimes quite cellular ; weUs 

 dug in this formation yield fetid, undrinkable water. In the ridges S. of 

 Fayette, towards Hamburg, we find chiefly gray clays, which sometimes appear 

 even on the summits of the ridges, but usually crop out on the hillsides and in 

 gullies. In several spots they contain veins and concretions of carbonate of 

 lime, but no fossils. 



235 2 In Franklin county, near Hamburg, we find only blue clays in the beds 

 of the streams, but urther S. & S. W., on the Homochitto and Wells' Creek, 

 sandstone is found in abundance — associated, however, with clayey strata, to 

 the mud formed by the disintegration of which, the ridge between the Homo- 

 chitto and Wells' Creek owes its sonorous name of " Devils Backbone." In 

 some localities in tins region, ledges of considerable thickness and uniformity 

 occur ; the rock from Dixon's Quarry, S. 40, T. 6, R. 2 E., which is of fine 

 quality, is scarcely to be distinguished from that of Grindstone Ford, ment ; oned 

 above ; it is almost perfectly white. 



236. According to Prof. Wailes, the ledges forming the Devils Backbone are 

 traceable in S. W. course, with little interruption, to Loftus' Heights, near Fort 



