part 1] THE WESTPHALIAK, ETC. OF EAST aLAMORGAl^. 57 



represented, Neuropteris and Sphenopteris being common, the 

 former genus slightly dominating the latter. Cordaite-leaves also 

 were well maintained in their distribution, and seeds belonging to 

 Cordaifes were common. Of the several classes of plants, the 

 rachis of ferns or fernlike plants slightly predominated over the 

 Equisetales. 



The No. 2 Rhondda Seam (Table X & fig. 11, pp. 52-53) crops 

 out a few feet above the brook-level at Grilfach Goch. Shales were 

 got from the mouth of the main roadway and inb3^e, 3200 yards 

 apart : the direction from the mouth of the level of the points where 

 the shales were observed was west and north-west. They were 

 obtained from 3 to 10 feet above the coal-seam. The shales are 

 dark grey and of a very fine grain, with abundant plant-remains. 

 Of the Equisetales, Aster opliyllites is again found dominating the 

 other genera of plants. Sphenophyllales are not by any means 

 rare. Lycopodiales are still poorly represented. Of the ferns and 

 fernlike plants Neiiropteris is the predominant genus. Cordaite- 

 leaves are now somewhat rarer than at the other horizons. The 

 Equisetales are once again superior in number to the plants of 

 the other classes. 



III. The Peoporttonal Distrtbution of Individual GtEnera 

 IN the Floral Assemblages of the Various Horizons. 



Calamites. — This genus is found frequently in the Five-Foot 

 Seam, and represents nearl}^ a sixth of the different genera of 

 plants. It increases rapidly in number in the Middle Yard Seam, 

 where it is found to reach its maximum at the different horizons. 

 The ITp])er Yard Seam shows a decrease in numbers, with a gradual 

 diminution in the Nine-Foot Seam, rapidly falling lower still in 

 the Six-Foot Seam ; but Calamites gradually increases in number 

 in the Two- Foot Nine and Pentre Seams respectively. 



In the Abergorky Seam, Calamites reaches its lowest ebb, but 

 gradually increases in number in the No. 3 and No. 2 Phondda 

 Seams. 



Asterophy ELITES. — The genus is somewhat scanty in the Five- 

 Foot Seam, occurs in great profusion in the Middle Yard Seam, 

 but diminishes rapidly in the Upper Yard Seam. The distribution 

 is found to be fairly wide in the Nine-Foot and Six-Foot Seams, 

 but the genus almost disappears in the Two-Foot Nine Seam, 

 which is the lowest point of its distribution. The Pentre Seam 

 shows an increase in the number of plants, and the maximum 

 is reached in the Abergorky Seam. After this Asteropliijllites 

 again becomes scantier in the No. 3 and No, 2 Phondda Seams. 



Calamocladus. — (The species now known as Aster opliyllites 

 char cef or mis was formerly known as Calamocladus char cBf or mis.) 

 The genus is very weak in the Five-Foot and the Middle Yard 

 Seams, then it entirely disappears in the Upper Yard, Nine-Foot, 



