$2 GEOLOGICAL STRUCTURE OF THE 



of Owensvillc, commonly called the Yellow banks, 

 the latter about 120 miles below Louisville on the 

 Ohio, still present traces of this extensive deposition, 

 though unaccompanied by the sand- stone and calca- 

 reous rock. On the west side of the Mississippi we 

 also discover the same marine alluvial formation in 

 the elevated banks of the Arkansa, on which the 

 town of Arkansas is situated, and which terminates 

 the great prairie, dividing the waters of this and 

 the White rivers. Still more lofty, and better cha- 

 racterized, are also the friable cliffs, called the Pine- 

 bluffs, commencing about 120 miles higher up this ri- 

 ver. Proceeding from hence in a southern direction, 

 we again meet with this alluvium on the banks of the 

 Washita, which gives rise to the Bovey-coal or lig- 

 nite mentioned in the voyage of Dr. Hunter and Mr. 

 Dunbar. In the calcareous platform of Red River, 

 which we found to constitute the basis of its plains, 

 both above and below the Confluence of theKiamesha, 

 we discover a great extention of this formation to the 

 west, and in some degree parallel with the indention 

 of the Mexican Gulf. This limestone presents all 

 the usual characters of friability, whiteness, argilla- 

 ceous admixture, and more recent shells such as 

 cardinms, pectinites and ostreas, as well as gry- 

 phites, terebratulites, and alcyonites. In a few 

 places along the immediate banks of Red River, it is 

 partially overlaid by hillocks of a conglomerate 

 abounding in horn-stone and other siliceous pebbles, 

 cemented principally by ferruginous matter. A more 



