282 GEOLOGICAL SURVEY OF THE TERRITORIES. 



The work was systematically begun and pursued, first, by the collection 

 and the examination of specimens of fossil plants in the different coal- 

 strata of the anthracite, where, in some cases, coal-beds, exposed in a 

 vertical position and therefore disconnected, were identified by their 

 vegetable remains only. The researches were then extended for com- 

 parison in different parts of the so-called Appalachian or bituminous-coal 

 fields of Pennsylvania, in order to ascertain if both basins, that of the 

 authracite and that of the bituminous coal, were positively of a same 

 formation, and if the distribution of the lossil plants could indicate 

 not only identity of period, but conformity in the deposits of the coal- 

 beds. These questions have been examined and answered in the intro- 

 duction to the fossil flora of the coal-measures in the final Report of the 

 Geological State Survey of Pennsylvania, and the data which were ex- 

 posed by these researches have been accepted as reliable and recog- 

 nized ever since. This is followed in the same introduction by the com- 

 parison of the Carboniferous flora of Europe with thatof Nortii America, 

 as far as this flora was then known, by more than one hundred species 

 described and figured in the Pennsylvania geological report, and by 

 as many more published in a catalogue of the fossil plants of the Coai- 

 Measures, by the Pottsville Scientific Association in 1858, and reprinted 

 in Professor Eogers's report. The intimate relation of the coal floras of 

 both continents is there discussed and forcibly established by the ex- 

 position of identity of types, even specific identity for the greatest 

 number of coal-plants. 



Later, vegetable i)aleontology was called to supply some evidence in 

 regard to the kind and degree of relation existing between the distribu- 

 tion of the measures of the so-called Appalachian coal-basin with those 

 of the ludiana and Illinois coalfields, to which belongs the western coal- 

 basin of Kentucky. Researches of the same kind were pursued by the 

 exploration of coal-beds and the determination of the specimens of fossil 

 plants found in connection with them. The results of this study have 

 been published long time ago in the geological reports of Kentucky, un- 

 der the direction of Dr. Dale Owen, and in those of Illinois, under that 

 of Prof. A. H. Worthen. They have exposed, not merely a general 

 relation of the coal plants of the western basins to those of the east, 

 but in most cases an identity of species, varied only by the jjresencc 

 of a number of rare, peculiar forms, remarked once only at a sole locality, 

 or seen again here and there, even at far distant points. This fact is 

 in accordance to the laws of geographical distribution, and repeated at 

 the different geological epochs as well as at this present time. These 

 researches have proved also the intimate relation of the coal-strata in 

 regard to their vertical distribution in both the eastern and westem 

 coal-fields, and therefore the synchronism of some of the moreimporta^it 

 coal beds over the whole extent of the North American Carboniferous 

 formations. Even then, from the harmony of distribution of the coal-strata 

 on both the eastern sides of the Indiana and Kentucky basin and the 

 western side of the Ohio Coal-Measures, as also from the identity of the 

 characters of their constituent plants, it had been inferred that the ip- 

 heaval of the Silurian ridge which separates them has succeeded che 

 formation of the coal, and that therefore these now separated coal-fields 

 have been originally united. This opinion has been contested on con- 

 siderations derived from stratigraphical evidence. I think, however, 

 that new discoveries, like that of strata of exactly the same composition, 

 with plants of identical species, as the Sub-Carboniferous fossil -bearing 

 beds of Perry County, Ohio, and of Port Byron, Illinois, will corrobo- 

 rate the conclusions dictated by vegetable paleontology. Anyhow, 



