§ 21. CARBONIFEROUS STRATA OF THE OOLITE. 515 



England, lignite and thin seams of coal are associated with 

 shale and laminated sandstones, so much resembling the an- 

 cient carboniferous beds, as to have led to an expensive and 

 abortive search for coal ; while in the north of Germany, the 

 Wealden contains a rich coal-field of considerable extent. 

 The fluvio-marine strata of Stonesfield, though teeming 

 with vestiges of land plants, enclose no considerable masses 

 of vegetable matter ; but in the extension of these lower 

 beds of the Oolite northward, indications of lignite and 

 carbonized plants become more abundant ; and along some 

 parts of the Yorkshire coast seams of coal and numerous 

 fossil vegetables occur ; proving that the currents of 

 fresh- water which flowed into that part of the oceanic 

 basin of the Oolite were occasionally loaded with trees 

 and terrestrial plants, transported from the lands inha- 

 bited by the Megalosauri, Pterodactyles, and small Mam- 

 malians, whose remains are found at Stonesfield. On the 

 western shores of Scotland, strata of a similar character are 

 exposed. 



Professor Phillips has fully described the carboniferous 

 beds of the Yorkshire oolite,* and Sir R. Murchison those 

 of Sutherlandshire ; the tabular arrangement, p. 492, show^s 

 the succession of the deposits in these two localities. 



In the district north of the Humber, the lower Oolite 

 assumes a new character : instead of finding beneath the 

 Cornbrash, the Forest marble and Great Oolite, we meet 

 with beds of sandstone, and shales abounding in coaly 

 matter, interpolated above the sand which covers the Lias. 

 Proceeding northwards, these strata rapidly increase in 

 thickness, and the carbonaceous layers gradually become 

 concentrated into a stratum of coal, which, though never 

 exceeding sixteen inches in depth, is, from local circum- 



* Encyclopaedia Metropolitan, art. Geology ; and the Geology of 

 Yorkshire, by the same eminent philosopher. 



VOL. II. M M 



