300 ASHLEY — GEOLOGY OF AKKANSAS. [May 13, 



west of Star-of-the-West a single piece of Trinity limestone was 

 found, and it is said that formerly such limestone was plentiful 

 at that locality. In 7 S., 32 W., or 33 W., near the north town- 

 ship line limestone full of fossils is reported as occurring plentifully 

 on a ridge west of Cross creek. This could not be verified. These 

 suggest the possibility of the Cretaceous deposits having been 

 originally laid down all over this region. This view is strengthened 

 by the character of the Cretaceous deposits, limestones, chalks, 

 etc., implying at least fairly deep waters over the region. 



Cretaceous and Tertiary Periods. 



During the Cretaceous and Tertiary periods the southern part of 

 Arkansas was the theatre of several gentle oscillations of level which 

 find record in the varying deposits bordering on the south. 



For the details of this history the reader is referred to the Survey's 

 reports on the Mesozoic and Tertiary.^ 



We must, however, note the land epochs, as it was probably dur- 

 ing one or all of these land epochs that the present drainage sys- 

 tems of our region were inaugurated and fixed. Two have been 

 noted during the Cretaceous and another follows the Tertiary sub- 

 sidence. 



Frequent references have been made to the way the main drain- 

 age streams cut across the structure, being influenced by the strike 

 of the folds only to a minor degree. In the novaculite area this 

 feature of the larger streams is still more marked, the Little Mis- 

 souri and Cossatot being good examples. In some cases these 

 streams cut across high ridges, when, by a short east or west offset, 

 they could have run around them. 



Remembering that the Cretaceous strata were originally much 

 thicker than they now are, if we replace these deposits, which have 

 a gentle south dip, they would doubtless extend well northward 

 toward or to the Ouachita mountains. Supposing now the move- 

 ment of elevation takes place. These new strata would gradually 

 become a land surface. Streams would start from the point of 

 highest elevation and run seaward. If a map of western Arkansas 

 and eastern Indian Territory be examined, it will be found that 

 there is such a centre from which drainage flows in all directions. 

 This centre is in the neighborhood of the Rich mountains, at the 



'^GeoL Stirv. of Ark., Rep. for 1888, VoL ii, p. 182; Rep. for 1892, Vol. ii. 



