1896.] 227 [Smith. 



The beds of Poteau mouiitaiu, ludiau Territory, are probably of the 

 age of the Lo-piiig strata, while the yellow shales of Scott comity, 

 Arkansas, 1 IST., 28 W., section 4, southeast quarter of southeast quarter, 

 are probably of the age of the Upper Carboniferous Limestone of Mos- 

 cow, and the west slope of the Urals,* if we can judge by the occurrence 

 of Gastrioceras conf. marianum and Pronorites in them. This would 

 make them older than the Poteau mountain shales, which is very likely 

 the case. They are the prol)able equivalents of the Canyon division of 

 Texas. 



P(( Icobota )i it' Ee iden ce. 



Our knowledge of the paleobotanj' of the Coal Measures of Arkansas 

 has been up to the present time very limited, depending almost entirely 

 on the publications of Lesquereux in the Second Annual Be2)ort of a 

 Geological Reconnoissance of the Middle and Southern Counties of 

 Arkansas, 1860, and in the Second Geological Survey of Pennsylvania, 

 "Report of Progress, P. Description of the Coal Flora of the Carbonif- 

 erous Formatio)! in Pennsylvania, and throughout tlie United States," 

 1884. 



The joint monographf of H. L. Fairchild and David White on tlie 

 Fossil Flora of the Coal Mc<(sur€s of Arkansas throws much new light 

 on the stratigraphic and regional distribution of species, and has been of 

 material aid in correlating the Arkansas strata with those of other 

 regions. They prove that all the Coal Measure plants:]: published from 

 Arkansas belong to the horizon of the Upper or Productive Coal Meas- 

 lu-es. The Van Buren plant l)ed is thought from paleobotanic evidence 

 to belong above the horizon from whicli most of the coal of Arkansas is 

 obtained, that of the Ouita coal, and this agrees with the evidence 

 given by the stratigraphy and the marine fossils. The Van Buren plant 

 bed occurs below the Poteau mountain marine beds, and above those in 

 8 N., 33 "W., section 12, Sebastian county, near Fort Smith ; and these 

 latter marine beds occur above the horizon of the Ouita coal. 



The Poteau mountain marine beds are of about the same age as the 

 Wyoming Valley limestouesg of the Upper Productive Coal Measures of 

 Pennsylvania, and these belong below the Dunkard creek series of the 

 Upper Barren Coal Measures. The Dunkard creek beds have lately 

 been proved by Prof I. C. White || to be of the same age as the Permian 

 of northern Texas, on the basis of plant remains that occur towards the 

 top of the Texas beds in which marine Permian fossils were found. T[ 

 But the paleobotanic evidence aids in establishing the age of the 



* C2 of Tschernischew, Mim. Com. Gcot. Bussie, Vol. iii. No. 4, p. :>)3. 

 t -\ii unpublished report of the Geol. Survey of Arkansas. 



J The work of the Survey shows that the plants described by Lesquereux from Wash- 

 ington county as Subconglomerate belong to the Lower Carboniferous. 

 i Upper part of C2, Tschemischew, Man. Com. Gi I. I^iissie, Vol. iii, No 4, p. 353. 

 li Bull. Geol. Sac. America, Vol. iii, p. 217. 

 1| Bull. 77, U. S. Geol. Survey. 



