May 28, 1897.] 



SCIENCE. 



851 



tical with American forms, although most of 

 these are cosmopolitan." The Slrophalosia of 

 this locality by its close relation to Australian 

 forms would indicate "a closer connection with 

 the Australian, or Southern, Carboniferous re- 

 gion than with the Pacific Province." 



But the classification and age of the Arkansas 

 Coal Measures is the most difficult problem the 

 author has to deal with and the most un- 

 satisfactory, being at best provisional. He 

 says: "The Coal Measures of Arkansas 

 have been temporarily classified by the Sur- 

 vey, for the sake of convenience, as Upper, 

 or Productive, and Lower, or Barren Coal 

 Measures. The division is not based on any 

 paleontologic or stratigraphic break, but merely 

 on the occurrence or non-occurrence of coal. 



"The divisions that are recognized in Penn- 

 sylvania could not be recognized in Arkansas, 

 but the strata of the two sections are correlated, 

 as far as possible, with the scanty data now at 

 hand. 



" Of the age of the Lower Coal Measures we 

 have only stratigraphic evidence, their position 

 above the limestone of the Lower Carboniferous 

 and below the coal -bearing beds of the Upper 

 Coal Measure being unmistakable. But their 

 known fauna and flora have been too limited 

 and indecisive to enable us to correlate the 

 stages with those of other Carboniferous areas, 

 since collections have been made in but few 

 places, and these chiefly in sandstones, where 

 the preservation of fossils is usually unsatisfac- 

 tory and the determination uncertain. 



" But the Lower Coal Measures correspond 

 in a general way to the Strawn and the lower 

 part of the canyon division of Texas, to the 

 Pottsville Conglomerate series, the Lower Pro- 

 ductive Coal Measures, and part of the Lower 

 Barren Coal Measures of Pennsylvania. The 

 series corresponds, in the main, to the Middle 

 Carboniferous limestone of eastern Russia." 



Concerning the Upper Coal Measures of Ar- 

 kansas, Professor Smith expresses the opinion 

 that they " correspond to the upper part of the 

 Canyon and the whole of the Cisco division of 

 Texas." He infers, from the presence of cer- 

 tain fossils, that the beds of Poteau Mountain, 

 I. T., are probably of the age of those in the 

 Lo-ping district, and that the yellow shales of 



Scott county, Arkansas, are probably of the age 

 of the Carboniferous Limestone at Moscow and 

 the west slope of the Urals. 



Under the heading, ' Paleobotanic Evidence,' 

 reference is made to an unpublished report by 

 Messrs. H. L. Fairchild and David White on 

 the Fossil Flora of the Coal Measures of Arkansas, 

 which "throws much new light on the. strati- 

 graphic and regional distribution of species, and 

 has been of material aid in correlating the Ar- 

 kansas strata with those of other regions. ' ' It 

 may not be out of place here to express the 

 hope that this monograph may soon be printed 

 ' ' They prove that all the Coal Measure plants * 

 published from Arkansas belong to the horizon 

 of the Upper or Productive Coal Measures." 

 The position of the Van Buren plant bed is 

 found to be below the marine beds of Poteau 

 Mountain and above those occurring in the vi- 

 cinity of Fort Smith, the last named horizon 

 being above that from which most of the coal is 

 obtained. While not entirely devoid of plant 

 remains, the rocks of the Lower Coal Measures 

 furnish but little evidence of a paleobotanical 

 kind suitable for correlation purposes. 



The Pacific Carboniferous sea is next dis- 

 cussed, including the following topics : Revo- 

 lution in Devonian Time ; The Carboniferous 

 Sea ; Upper Carboniferous in the West ; The 

 Pawhuski Limestone ; The Interchange of Life 

 between East and West (the most striking 

 topic) ; Replacement of Limestone by Coal-bear- 

 ing Formations in Western Europe ; and Land 

 Areas in the West. The Permian Pacific Ocean 

 and the Triassic Pacific Ocean are also touched 

 upon. 



As to the time of the Ouachita Uplift Profes- 

 sor Smith writes : " The youngest rocks known 

 to take part in the Ouachita Mountain system 

 belong to the Upper Coal Measures, and the 

 disturbance must have taken place at the border 

 between the Carboniferous and the Permian. 

 Still it is not unlikely that deposits of Permo- 

 Carboniferous age may yet be found at some 

 places in that region. * « * 



" This uplift may be of the same age as that 

 movement in the Appalachians which cut ofl" 

 the Upper Barren Coal Measures of Pennsyl- 



* Exclusive of those described from Washington 

 county. 



