305 lyiGNiTic Stage 13 



minus of this ravine there are high bluffs along the right bank 

 of the Ouachita which are difficult of ascent, and often perpen- 

 dicular. This is especially true of those just below where they 

 rise about 70 feet above the river at a mean stage. 



These will suffice to show the general nature and character- 

 istics of the Lrignitic beds of Arkansas. 



Missouri. 



We have little or no definite knowledge regarding the Tertiary 

 of Missouri, though the lowlands of the southeastern portion 

 are supposed to be underlaid by beds of this and perhaps the 

 Cretaceous age. We are gratified to know that the present 

 State Geologist is about to take this matter in hand, and it is 

 to be hoped that this portion of the State will soon be mapped 

 and its fossil faunas made known. 



Illinois. 



Referetices : — Geological Survey of Illinois, vol. i, p. 44 et al., 

 1866, — Worthen. Geological Survey of Ken- 

 tucky, Report on fackson's Purchase Region, 1888, 

 pp. 4^-46, — Loughridge. 



We have not personally visited the Tertiary deposits of this 

 State and cannot say to what stage they belong, but it is reason- 

 able to suppose that they should be classed as Midway or Lig- 

 nitic or probably as both. The siliceous gravels and conglom- 

 erates remind one strikingly of those found in southwestern 

 Arkansas. Worthen says : ' ' This system [ Tertiary] has only 

 been identified in the southern portion of the State, and ap- 

 pears to attain its greatest development in Pulaski county, 

 where it is represented by a series of stratified sands and clays 

 of various colors, with beds of siliceous gravel, often cemented 

 into a ferruginous conglomerate by the infiltration of a hydroxyd 

 of iron. A marked feature of this system, in Pulaski county, 

 is the presence of a bed of green marly sand, which from its litho- 

 logical characters was at first supposed to be the equivalent of 

 the Cretaceous green sand of New Jersey. An examination of 

 the fossils which it affords, however, seems to leave no doubt of 

 its Tertiary age. They consist of marine shells, belonging to 

 the genus Cucullcsa and Turritella, in the form of casts, the 



