230 Mr. Williamson on the Distribution of 



(b.) Ironstone, containing a large species of Calamites, fronds of Zamia gigas, 

 and remains of a remarkable fossil, apparently connected with the fruc- 

 tification of a Cycas 20 feet. 



(c.) Hard, pale, gritty sandstone 20 



(d.) Shale 10 



(e.) Gritty sandstone resembling the bed c 20 



(/.) Soft yellow sandstone, containing stems of Equisetum columnare in a ver- 

 tical position, with their roots downwards 8 



[The opinions respecting these stems being deposited perpendicularly, are various ; but that 

 given by Professor Phillips, and urged by Mr. De la Beche in his Geological Manual, appears 

 to me the most probable ; viz. — that the plants were transported to their present positions, and 

 deposited with their roots downwards, in consequence of the greater specific gravity generally 

 possessed by the roots of this class of plants. The upper extremities being all broken off, afford 

 rather a strong proof of their having been exposed to the action of disturbed water. We should 

 expect to find the same effect produced upon the delicate vascular Equisetas of the present day. 



The place whence they have been transported, cannot however have been far distant, or they 

 would have been still more disjointed and compressed ; on the contrary, they often retain all 

 their original roundness.] 



{g.) Black shale 3 feet. 



(/«.) Sandstones and shales of varying thicknesses. The sandstones are hard, 



fissile, and used as flags ; total thickness about 170 



(i.) Resting upon this series is another group of sandstones and shales ; divided 

 as follows : — 



The lowest part, dark shaly sandstone 8 feet. 



Harder, gray sandstone 6 



Laminated sandstone, which contains numerous remains of beau- 

 tiful ferns and cycadean plants 6 



The following is a list of plants obtained from the group : 

 Equisetum laterale. 

 Lycopodites Williamsonis. 

 falcatus. 



Thuytes expansus. 

 Sphenopteris ? longifolia. 



hymenophylloides. 



Neuropteris ligata. 

 Pecopteris curtata. 



— . Whitbiensis. 



Williamsonis. 



Pterophyllum pectinoides. 



minus. 



Zamia lanceolata. 

 Otopteris acuminata. 

 Cyclopteris digitata. 

 Taeniopteris vittata. 

 Solenites Murrayana. 

 Tympanophora racemosa. 



simplex. 



Seeds of a Cycadites*. 



The superior strata of inferior oolite composed of about 1 70 feet of sandstone and shale, con- 



* Towards the lower part, it also contains thin seams of jet, of a quality inferior to that procured 

 from the lias. 



