I,es.|ucreii.\.J 410 [Jan. 5, 



teresting data procured refer to the discovery in our carboniferous measures 

 of species of plants which have been until now considered in Europe as char- 

 acteristic of more recent formations. Thus we have in the sub-carboniferous, 

 under the Chester limestone of Illinois, leaves referable to the genus Glos- 

 sopteriK, as described by Brongniai t, and remarkably similar to those of his 

 6. NilUoniitna. This genus, saysSchimper, has no analogous in the present 

 vegetation, and its existence appears limited to the first half of the Juras- 

 sic period. This is remarkable indeed ; and it might be supjwsed that 

 though the specimens of this species are very clearly defined in their char- 

 acters, they may represent a different and new type with a mere casual 

 likeness. But we have at Morris, from the first coal above the mill- 

 stone grit, a fine leaf of Phlebopteris {Dictyopltyllum), preserved in its in- 

 tegrity, with i'lS distinct characters, the peculiar nervation not remarked in 

 any other genus. And this genus is also Liassic, for Europe at least. Beside 

 this, the coal of Morris is related to the Permian of Europe by a number of 

 identical types, a fact remarked already by Schimper. The species of Spi- 

 rangiuin, for example, are not rare in the nodules of Mazon creek. From the 

 sub-carboniferous of Alabama and of Pennsylvania we have two species of 

 TiMiilopterix, a genus also considered in Europe as limited to the Permian. 

 This enumerati(m might be pursued farther ; but the peculiarities of distri- 

 bution will be better understood when accompanied by the description of 

 species, and by the notes upon their relationships. 



From the remarks made already it is easily understood that the docu- 

 ments concerning the geographical distribution of the species of the coal 

 flora have been carefully searched for and recorded. They are already val- 

 uable for comparing the characters of the vege:ation, not only in the diflTer- 

 cnt basins in North America, but of Europe also. To elucidate this (lues- 

 tion as far as possible stations, fixed at distant localities, and where long 

 and persistent explorations have been pursued, are especiall}' valuable. 

 With the station of Newport, Rhode Island ; that of Cannclton, Pennsylva- 

 nia ; of Morris, Illinois ; of Clinton, Missouri ; of Pomeroy, Ohio; of two 

 localities in the coal mines of Alabama, we may expect to find by compari- 

 son of the floras reliable documents in regard to the question of the hori- 

 zontal or geographical distribution of the species. 



The last and more important question refers to the stratigraiihical distri- 

 bution of the coal plants; and to it belongs, as a postulate, that of the possi- 

 bility of determining the relative horizons of the coal beds from the vege- 

 table fossil remains possibly discovered in connection with them. This 

 question has been for a long time, and is still, at i.ssue among European 

 paleont')logist8, who are generally inclined to admit that there is or 

 8h:)uld be a marked diversity in the floras of coal strata of different ages or of 

 different horizons. Imbued with this persuasion I began researches in 

 Pennsylvania with the idea that in a fair and open field like that of our car- 

 boniferous measures, which are exposed to e.vploralion, souielinus for great 

 thicknesses of stra'a, and besides, over very wide areas, a problem of this 

 kind should be easily solved. My belief in the applicability of paleontology 



