GEEAT OOLITE PLANTS. 77 



Stonesfield in Oxfordshire, where a fine-grained shelly sandstone 

 has been quarried for roofing-slates for many centuries. In his 

 Natwal Sistory of Oxfordshire, Plot' makes the following 

 reference to the slates of Stonesfield : — " But before we take leave 

 of materials for building, we must not forget that the houses are 

 covered, for the most part in Oxfordshire not with tiles but 

 flat-stone, whereof the lightest, and that which imbibes the water 

 least, is accounted the best. And such is that which they have 

 at Stonesfield, where it is dug first in thick cakes, about Michaelmas 

 time, or before, to lye all the "Winter and receive the frosts, which 

 make it cleave in the Spring following into thin slates, which 

 otherwise it would not do so kindly." 



The fossil plants of the Stonesfield Slate have been found chiefly 

 at Stonesfield, Sevenhampton Common, and Eyeford; they occur 

 in a marine sediment rich in the remains of mammals, reptUes, 

 insects, and molluscs. It has been suggested that the Stonesfield 

 flora may represent the fragmentary relics of the vegetation of an 

 islet in the Jurassic sea. The frequent occurrence of detached 

 leaflets and the fragmentary condition of the plants may perhaps 

 be regarded as evidence in favour of the view that the area of 

 deposition was a considerable distance from the land on which the 

 vegetation flourished ; or it may be that the land rose steeply from 

 the water's edge, and the branches, leaves, and seeds were thus 

 exposed to rough usage by the rivers that swept them into the sea. 



In Buokland's paper on the Megalosawrus or Great Lizard of 

 Stonesfield, the plants are mentioned but not described.' 

 Brongniart, in his Prodrome, speaks of the Stonesfield plants 

 as being of rather later date than those from the Yorkshire coast, 

 but he recognises the close agreement between the two floras.^ 



In Murchison's Outline of the Geology of the Neighlowrhood 

 of Cheltenham, published in 1834,* no account of the plants is 

 included ; but in a new edition " augmented and revised by 

 James Buekman and H. E. Strickland," ^ the following species are- 



' Plot (1677). 



2 Buckland (24), p. 392. 



' BrongDiart (28), p. 197. 



♦ Murchison (34). 



^ Mui-chiaon, Buekman, and Stiickland (45). 



