^ii IX) <V A A C A D f. \! r O F SC f F. !S CK S . 



^iill" found a westei'n limit at tli<' paltoo/.oic csraritnionl wliiCfn 

 is approximately, if not exactly, iudicatod in the state of Ar- 

 kansas by the railway line above named. From Xewi)oit 

 southwards to uear Little Koek, the strata eomposing the oldest 

 series of tertiar}' roeks — to which series the subjacent strata 

 throughout this area belong — lie uncomformal)ly upon carbon- 

 iferous shales and sandstones. At and about Little Rock these 

 same strata lie in direct relation to slates of possibly similar 

 g(M)l<)gic age and also t<y erjstalline rcx-ks of uncertain age. 

 Southwestward from the ea[)ital of the State to near Arkadel- 

 i^hia and onwards to the State line near Texarkana the strata 

 lie comformably upon rocks of cretaceous age. So gradual is 

 the cliange in the macroscopic and lithologi<; characters of 

 the rocks along the Ouachita at Arkadelphia that the line 

 of demarkation between the cretaceous and tertiarj' cannot 

 possibly be drawn. Here, if anywhere in the State, is to be 

 seen absolute conformity both in stratigraphic and chronologic 

 sequence. 



No eii'ort has been made herein to correlate the various sub- 

 divisions of the tertiary in this State with the divisions rec- 

 ognized by other observers. Such correlation would be pr<v 

 mature, and would be authentic only after very extended and 

 careful observations on the whole tertiary area of the State, 

 while as above noted our o1)sei-vations have l)een somewhat 

 limited in res[)ect to area. It nnist suftice to say that the 

 study made shows that the tertiary series included within the 

 .scope of this report Ix^long to the eo-lignitic of recent writers 

 and that possil)ly the Jacksonian group, now considered to 

 attain its most northern extension at Helena, in Philli[)s 

 County, outcrops in the southwestern j)ortion of (.May (\nmty. 

 that is, must be extended northward more than one hundred 

 and forty miles. 



One other general conclusion is here deserving of mention. 

 viz: Whatever distinctions or divisions are, in the future. 



