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ages, and thus the associated clays were turned into shales, and the 

 plants converted into coaL Besides vegetable remains, the coal measures 

 contained numerous other fossils, sauroiJ fishes, with powerful jawa and 

 teeth, as large as crocodiles ; and various examples of the shark tribe, 

 ■with some reptiles of a low class, Archegeosaurus, &c., mixed more 

 or less with marine and estuarine shells. Land shells were very 

 seldom found, which militates rather against the lake theory of the coal 

 formation. Dr. Dawson, of Montreal, from the fact of the occurrence 

 of such an abundance of stigmaria (roots of the sigillaria) in the 

 "under clay" which is found beneath all coal beds, contends that the 

 coal was accumiilated by growth, in situ, and not drifted there, the clay 

 being formed by the transportation of the mud and sand by water, conditions 

 which may now be seen to prevail in the swampy deltas of great rivers. 

 The cannel coal and earthy bitumen, he states, are of the nature of the 

 fine vegetable mud which accumulates in the ponds and shallow lakes of 

 modern swamps. Fresh water shells are very rarely if ever found, but 

 Dr. Dawson had found a pupa, a land shell, and many small reptiles, in 

 the hollow trunk of a sigillaria. It was a very small shell, but it was a 

 very important fact. Insects had also been detected in the coal, but they 

 were exceedingly rare in the English series. A fossil spider had been met 

 with in Germany in a very perfect state, the round full body, 

 the legs, and palpi all beautifully preserved. Scorpions and various 

 other insects had also been found in the coal shales. A knowledge 

 of the different formations in connection with coal was of the utmost 

 importance, ordinary miners judge so commonly from appearances on the 

 surface thac they were always liable to be deceived themselves as to the 

 probability of finding coal, if they did not sometimes wilfully deceive others, 

 as he believed they did. Near Wenlock, for example, a gentleman had been 

 persuaded to bore for coal into rocks below the coal formations. He cut 

 down the trees on his estate to pay the expenses, under the influence of the 

 Staffordshire miner who induced him to try for it, and who would occa- 

 sionally bring up small pieces of coal in his pocket. It was of no use to tell 

 him that he was below the coal, and that it could never be found there. He 

 went on boiidg, and continues to do so to this day, for anything the 

 lecturer knew to the contrary. 



The association of beds of ironstone with coal was a most remarkable 

 fact, and of the highest importance in a practical point of view, though it was 

 by no means clear from whence the iron was derived, possibly from chalybiate 

 waters or decomposed vegetation. 



Besides the use of coal as a fuel, there was another great fact in con- 

 nection with it, and that was the production of mineral oils in enormous 

 quantities from the coal fields of North America. This discovery had proved 

 of the highest value and utility and had developed a trade of its own. 



