|)art ij THE WESTPHALIA^-, ETC). OF EAST GtAMOEGAN. 



67 



Name of seam. 



Percentage composition 

 of flora. 



Probable phi/sical 

 conditions. 



Pentre Seam 



Equisetales 25'99 p. c. 



Splienopliyllales 6'49 p. c. 



Lowland conditions prevailed, 

 with slight undulations bor- 







Lycopodiales ... 38'71 p. c. 



dering large marshes. The 





Filicales and 



increase in the number of 





Pteridosperms 9"97 p. c. 



Filicales and Pteridosperms 





Cordaitales 18'68 p. c. 



is marked, and suggests a 

 period of gradual upheaval 

 of the land-surface. 



Abergovlc)^ Seam 



Equisetales 82'41 p. c. 



An undulating land -surface 





Sphenophy Hales 0'40 p. c. 



with very few marshes. 





Lycopodiales ... 0"21 p. c. 



The elevations could not 





Filicales and 



have been of any great ex- 





Pteridosperms 5'13 p. c. 



tent, as the ferns and fern- 





Cordaitales 9"6 p. c. 



like plants are scarce. It 

 does not always follow that 

 the general outline of the 

 surface, although of low- 

 land character, shows the 

 existence of marshy con- 

 ditions, as the Lycopods 

 are rare. 



No. 3 Rliondda Seam . 



Equisetales 37"19 p. c. 



A period of rising land- sur- 





Spheuophyllales 1'09 p. c. 



face resulting in high ele- 





Lycopodiales ... 0'25 p. c. 



vations which would be 





Filicales and 



well clothed with ferns and 





Pteridosperms 42"13 p. c. 



fernlike plants. Their pre- 





Cordaitales 20'10 p. c. 



ponderance over the other 

 classes would be great 

 under such conditions. 

 Marshes of small area 

 would be met with in the 

 tracts of low land where 

 the Lycopods flourish. A 

 marked contrast is notice- 

 able here between the Lyco- 

 pods and the fernlike plants. 



No. 2 Rhondda Seam . 



Equisetales 41'56 p. c. 



A slightly depressed land sur- 





Spheuophyllales 6'64 p. c. 



face prevailed here, as com- 





Lycopodiales ... 1"23 p. c. 



pared with No. 3 Rhondda 





Filicales and 



Seam times. The marshy 





Pteridosperms 35'89 p. c. 



areas were not very pre- 





Cordaitales 14'68 p. c. 



valent, and the Lycopods 

 are still rare. A period of 

 possibly subsiding land- 

 surface occurs, which gives 

 rise to a gradual decrease 

 in the growth of ferns and 

 fernlike plants. 



.1 



It will be observed from the foregoing synopsis that the Equi- 

 setales dominate the other classes, four times, in the Middle 

 Yard, Nine-Foot, Abergorky, and No. 2 Rhondda Seams. 



The Sphenophy Hales are rare, and are only met with at five 

 horizons, namely, the Middle Yard, Pentre, Abergorky, No. 3 

 Rhondda, and No. 2 Rhondda Seams. 



The Lycopodiales dominate the other classes twice, in th<^ Two- 

 Foot Nine and Pentre Seams. 



