14 GEOLOGICAL REPOET. [122, 23, 24 



22. Usually, the pebbles occur in loose beds, commingled with 

 sand, clay, or clayey sand : and in its western belt, along the 

 Mississippi River, it is only very locally that they are at times 

 found cemented, to a certain extent, by a ferruginous sandy cement, 

 where an impervious vein traverses the stratum. In eastern 

 Tishomingo county, however, they are very commonly cemented 

 into a pretty lirm conglomerate or puddingstone, by a cement of 

 brown hematite, with very little sand. This conglomerate forms 

 some high hills and ridges, and precipitous cliffs, on the territory 

 of the Carboniferous formation in the county mentioned ; and it is 

 occasionally seen, through eastern Itawamba, and Monroe counties, 

 as far south as Buttahatchie Creek. A more detailed account of 

 the peculiar features of the Orange Sand formation in eastern 

 Tishomingo, will be given below. (1 30 & ff.) 



23. A singular rock belonging to this formation, and much resembling a true 

 puddingstone, is found in a few localities in W. Tippah and E. Lafayette 

 counties, on the territory of the Lignitic Tertiary, (e. g. S. 1, T. 5, R. 2, E. 

 Tippah count}' ; S. 33, T. 1), It. 1, W., Lafayette county.) It consists of a 

 ferruginous and somewhat sandy cement, in which are imbedded numerous 

 rounded concretions of a pisolithic structure, formed of concentric layers of a 

 siliceous material, more or less ferruginous, and in some almost white ; the 

 largest being about 3 4 inch in diameter. 



24. Clay Deposits. — Clay has been repeatedly mentioned as 

 occurring within the Orange Sand formation ; and although this 

 material does not usually form heavy deposits, and cannot therefore 

 vie with the others mentioned as to quantity, the great frequency of 

 its occurrence, as well as its practical usefulness in numerous 

 cases, renders it second in importance to none. The clay deposits 

 of the Orange Sand are most common in (though by no means 

 confined to) its lower stages ; they rarely extend over large areas, 

 save that at times, their layers, often ineontir.uous, intervening 

 between adjacent strata of sand, may be traced, under favorable 

 circumstances, with little change of either quality or quantity, for 

 a mile or two. As a general thing, the larger masses of clays 

 appear in basin-shaped, lenticular, or nodular masses, when occur- 

 ring independently of other formations ; the only notable exception 

 to this rule, known to me, are the white and red clays of the 

 carboniferous territory, in Tishomingo, which form strata extend- 

 ing over considerable areas, aed of unusual thickness. 



