COMPOSITION OF THE MISSOURI FLORA. 289 



epoch have been specially discussed by Hall,* Winslow,t Broadhead,J 

 and Keyes.§ From the observations of these geologists it appears that 

 in this region the early Mesocarboniferous time was marked by a general 

 subsidence, the result of which w r as the concealment of the earliest Coal 

 Measures strata by the overlaps of the succeeding terranes. The plants 

 from these fossiliferous beds fringing the old irregular shore, with which 

 in places they came in almost direct contact, mark therefore the time 

 when the incursion of the Mesocarboniferous sea overwhelmed the vicin- 

 ity of Clinton. Thus they serve as criteria for the approximate determi- 

 nation of the close in this district of that period of post-Mississippian 

 erosion. 



COMPOSITION" OF THE FLORA. 



The examination of the plant collections from the coals under consid- 

 eration reveals a flora of 123 species, || the general characters and S3 r s- 

 tematic range of which will be seen from the following abridged generic 

 synopsis : 



Flxgi : Calamarie.e: 



Hysterites, 1. Catamites, 3. 



Extipulites, 1. Aster ophyll'iles, 3. 



Ferns* Calamostachys, 1. 



Eremopteris, 2. Annalarm, 3. 



Pseudopecopteris, 2.fl Macrostachya, 2. 



Mariopteris, 4. Radiates, 2. 



Sphenoptcris, 19. Sphenophylle.e ; 



Oligocarpia, 3. Sphenophyllum, 4. 



Pecopteris, 13. Vulkmannia, 1. 



Lepidodendre.e : 



Lepidodendron, 5. 

 Lepidophloios, 2. 

 Lepidostrobus, 3. 

 Lepidophyllum, 2. 

 Oinphalophloios, 1. 



Brittsia, 1**. 



Caulopteris, 2. 



Megaphyton, 1. 



Aphlebia, 8. 



Alethopter'ix, 2. 



Callipteridium, 5. 



Odontopteris, 1. 



NeuropteriSj 5. Sigillarie.e : 



Didyopteris, 1. Sigillaria, 4. 



Tseniopteris, 1. Stigmaria, 2. 



* Am. Jour. Sci., vol. xxvii, 1857, p. 197. 



t Bull Geol. Soc. Am., vol. 3, 1892, p. 109-121 ; Am. Geologist, vol. xv, pp. 81-89 ; Preliminary Re- 

 port on Coal, 1891, p. 19. 



X Am. Geologist, vol. xiv, 1894, pp. 380-388. 



£Am. Geologist, vol. xii, 1893, p. 100. 

 Since most of the species found in the shales over the higher coal are identical with those 

 found in the lower coal, as might be expected from the proximity of the two horizons, the com- 

 bined species will be regarded as one flora in the present comparisons, in which only the general 

 stage of the floras is considered. 



11 Emended and redefined. 



** New genus. 



