THE ORANGE SAND FORMATION. 



G. As has been stated above, the Orange Sand formation 

 characterizes the greater part of the surface of the State of 

 Mississippi- It is entirely wanting only in the alluvial bottom of 

 the Mississippi River ; and it occurs to a limited extent only in the 

 following districts : 1st, In the territory of the Bluff formation, 

 skirting the Mississippi River southward of vicksburg, to the 

 Louisiana line. Above Natchez, the Orange Sand formation 

 usually runs out at a distance of 8 or 12 miles from the Mississippi 

 River, where it appears underlying the calcareous silt of the Bluff 

 formation, sometimes only a few inches in thickness, but increasing 

 rapidly as we advance inland ; below Natchez, however, we find it 

 forming a high Bluff of considerable extent (the White Cliffs) on 

 the Mississippi River itself ; and at Fort Adams, on Loftus' Heights, 

 it appears in a stratum about 90 feet in thickness, overlaid by a 

 stratuir 73 feet thick, of the materials of the Bluff formation. It 

 probably appears on many intermediate points also. — 2d, In the 

 territory occupied by the Jackson Group of the eocene tertiary. 

 It is absent from the prairies of this district, (whether of the 

 gypseous or caleareous character), but usually forms the ridges 

 skirting them ; it is wanting also, in the "Hog- Wallow- Prairie' 7 

 district of the same region, in N. E. Smith and N. W. Jasper 

 counties, but nevertheless forms all the ridges bordering on the 

 same. — 3d, It is wanting in a large portion of the territory occu- 

 pied by the Rotten Limestoue Group of the cretaceous formation, 

 viz : on the prairies, and the gently undulating oak uplands 

 skirting them. And finally, it is absent, or but feebly represented, 

 4th, In the "Flatwoods" region, and particularly, in the "Flatwoods 77 

 proper. In remaining portion of the State, the ground is either 

 occupied by the members of the Orange Sand formation, or else, 

 when the more ancient strata form ridges by themselves, it is only 

 in limited patches. Very frequently, the older deposits form the 

 beds of the streams, where they crop out in bluffs ; constituting also 

 the lower portion of the hills, which are capped with Orange 



