416 Expedition to the 



hitherto been found, has resulted from the disintegration of a 

 sandstone of this kind. 



Sandstone, though often covered at the surface by compact 

 limestone, or some other rock, is probably the stratum which 

 occurs in greatest quantity, throughout every part of this 

 range of mountains. It is the prevailing rock, in all the coun- 

 try between, the Arkansa and Red rivers, from the confluence 

 of the Mamelle westward, rising to the height of two or 

 three thousand feet, to form the summits of the Cavanid, 

 Sugar loaf, and Mt. Cerne and to a less considerable ele- 

 vation,, at the Mamelle, Magazin, Castete and Short moun- 

 tains. 



North of the Arkansa, it forms the body of the Chatta- 

 hooche mountain, and of many nameless elevations, which 

 diversify the sujface from the sources of the Little Red river 

 to the Mississippi. Beds of coarse conglomerate or pudding- 

 stone, are met with in many places, but these are particular- 

 ly frequent in connexion with the inclined sandstones about 

 the Washita. 



IV. — Native Argil? 



Nine miles west of Bainbridge, on the road to Jackson, 

 and on the right bank of the Mississippi, near the head of 

 Tiawapeti bottom, also in various other places in this vici- 

 nity, are extensive beds of perfectly white substance (ap- 

 parently argil), of about the hardness of common chalk, for 

 which it has often been mistaken.* 



* See " Schoolcraft's Catalogue of Western Minerals," art. i, p 279. 



A very exteosive bed oi native argil occurs on the right bank of the 

 Mississippi, commencing' near the head of Tiawapeti bottom, at the Little 

 Chain, about forty miles above the junction of the Ohio and Mississippi, 

 and extending, with very little interruption, near six miles above the 

 Grand Tower, a distance of thirty-four miles. Beyond these limits, I have 

 not observed it. Its colour is snow white; structure, fine pulverulent; frac- 

 ture, dull earthy. It is amorphous, and adheres to the tongue. It does not 

 elfervesce with acids, even in the slightest degree. The bed of argil re- 

 poses on horizontal strata of silicious sandstone, and shell limestone 

 occurs near it. In the vein of argil, nodules and veins of flint aie arranged, 

 as to make, with the horizon, an angle of about fifty degrees. The argil 

 has been taken to iSevv Orleans, Pittsburgh, St. Louis, «l!ic. in considera- 

 ble ciuantiiies, being mistaken for chalk, for which substance it has been 

 used. 



Mr- Jessup's MS. Report. 



Flint. — This occurs in nodules and veins, in a bed of native argil, above 

 Tiawapeti bottom. Its colours are blaisli gray, aud greenish black- It gives 



