FOSSIL PLANTS. 507 



rate coal basins of Western Kentucky, Illinois and Michigan with our eastern 

 coal fields ? The first two of these questions have been examined and answered 

 in the Geological Report of Pennsylvania, pp. 839-842. Though new discove- 

 ries might now furnish some interesting details to the discussion, nothing has 

 as yet been found in the Coal Measures, which might tend to invalidate the 

 conclusions admitted in that report. The third question has been also consid- 

 ered* from data obtained in the geological explorations of Kentucky, Arkansas 

 and Indiana, and therefore I have but to add here a few remarks which are 

 called for by the species recently found in the Coal Measures of Illinois. 



We cannot expect to trace any marked differences indicating climatic divi- 

 sions from the northern to the southern limits of the coal fields of Illinois. 

 Local changes, as indicated from the table of distribution, can but be consid- 

 ered as casual, and not ascribed to any permanent or general thermal influence. 



The relation of the Coal Measures of Illinois with the eastern coal fields of 

 Pennsylvania, Rhode Island and Nova Scotia, is indicated not only by the com- 

 mon or more predominant species, but also by some rare and striking ones. 

 The coal of Morris, for example, has, in common with that of Newport, R. I., 

 Pecopteris squamosa, Pecopteris unita, Odontopteris Schlotlieimii and Asterophyl- 

 lites loBvis ; with the low beds of anthracite of Pennsylvania, Callipteris Sulli- 

 vantii, Neuropteris Jimbriata, N. rai'wervis, N. Clarksonii, N'. Desorii, etc., 

 and with the Coal Measures of Nova Scotia: Odontopteris subcuneata, a species 

 not seen as yet in any other part of the coal fields of the United States. Some 

 species of the eastern basin, lilce Neuropteris Rogersl, Lesqx., Odontopteris 

 aluta, Lesqx., Alethoptei-is obscura, Lesqx., Whittleseya elegans ,Newb. 5 etc., have 

 not yet been found in Illinois but these are very rare species, discovered each 

 at a single locality, as are some of the new species described from the coal fields 

 of Illinois, and which may be found elsewhere hereafter. Illinois has likewise 

 about 30 species known in the coal flora of Europe, and which have not been 

 yet seen in the more eastern coal fields of America. 



Of the common species of our eastern coal fields, not yet found in Illinois, 

 none can be quoted but Dictyopteris obliqua, Bunb., locally abundant in the 

 shale of the high coal near Pottsville, Penn., of Newport, R. I., and of the sub- 

 conglomerate coal of Arkansas; Sphenopteris artemisvEfolia, Brgt., rare every- 

 where, sparingly found in the low beds of the anthracite basin of Pennsylva- 

 nia and of the western coal fields of Kentucky ; Pecopteris arborescens, already 

 quoted; Pecopteris Loschii and the peculiar Brackyphylkim obtitsum, Lesqx., 

 both locally predominant in the anthracite fields. The near relation of the coal 

 basin of Illinois with the other coal fields of this continent, is thus demonstra- 

 ted by its fossil flora. 



* Journal of Science and Art, July, 1860. 



