COMMENCEMENT OF LAND PLANTS. 49 



era. There might be patches of vegetation long before the 

 time of the great coal flora ; and from such pieces of land 

 might those early specimens have been wafted. 



The Carboniferous formation exhibits a scanty zoology 

 compared with either those which go before, or those which 

 come after. The mountain limestone, indeed, deposited at 

 the commencement of it, abounds unusually in polypiaria, 

 crinoidea, and mollusca ; but when we ascend to the coal- 

 beds themselves, the case is altered. We have then only a 

 limited variety of shell mollusks, with fragments of a few 

 species of fishes, and these are rarely or never found in the coal 

 seams, but in the shales alternating with them. Among the 

 fishes, the conspicuous form is the Sauroid family, which receives 

 its name in consequence of a character of teeth, scales, and 

 even osteology, resembling that of the Sauria, and evidently 

 leading on to that section of reptiles. ( 27 ) One of the most 

 noted species is the Megalichthys Hibbertii, discovered by 

 Dr. Hibbert Ware, in a limestone bed at Burdiehouse, near 

 Edinburgh, and of which other specimens have been found in 

 the coal measures of Yorkshire, and low coal shales of New- 

 castle. The enormous size of the animal is inferred from 

 teeth belonging to it, not less than four inches long. At this 

 point we find the first traces of land animals, in the fossil re- 

 mains of terrestrial insects ( 28 ) and the foot-prints of reptiles, 

 the first in England, the latter in America. ( ?9 ) 



Coal strata are nearly confined to the group termed the 

 carboniferous formation. Thin beds are not unknown after- 

 wards, but they occur only as a rare exception. It is there- 

 fore thought that the most important of the conditions which 

 allowed of so abundant a terrestrial vegetation whatever 

 these were had ceased about the time when this formation 

 was completed. 



The termination of the carboniferous formation is marked 

 in some regions by symptoms of great disturbance. Coal- 

 beds generally lie in basins, as if following the curve of the 

 bottom of seas. There is no such basin which is not broken 

 up into pieces, some of which have been tossed up on edge, 

 others allowed to sink, causing the ends of strata to be in 



