130 



THE GEOLOGIST. 



Dr. Williamson found that this pith was imbedded in a wood which 

 was in all respects a true fir-tree, and which has been known under the 

 name of Dadoxylon. It is not certain that all the firs belonged to this 

 one genus ; most probably they did not. At all events Dadoxylon is 

 a very common coal-fossil. 



Here then we have the wood and the pith ; and let me say that 

 any one who is disposed to examine the contents of his own coal 

 scuttle may do so with advantage, for the charcoal he will find in it 

 shows, under the microscope, a beautiful tissue like that described 

 above. As an opaque object it is very beautiful, and polished slices 

 sometimes show it equally well. Prof. Queckett, of the College of 

 Surgeons, has distinguished himself for his researches into these 

 tissues, and in the wonderful " Torbane Hill case," referred to in 

 the opening of this lecture, his skill was largely called into 

 requisition. 



But having got the wood, one naturally wishes to find the leaves 

 and seeds. What were they ? 



Some years back a suspicion entered my mind that the leaves 

 commonly called Gyclopteris might belong to this family of trees. It 

 is true they might be ferns, to which order they have been usually 

 referred. But there are fir-trees, or at least Coniferas, which have 

 broad leaves very much of the shape of these supposed ferns. Heart- 

 shaped or fan-shaped leaves, with a shorter or longer stalk, and the 

 veins so like that of the fern, that it is difficult to distinguish frag- 

 ments. These are the Salisburia. They are trees well known in our 

 parks and gardens, and there is a noble specimen at Kew. Let 

 anyone compare a figure of the Cyclqpteris of the coal with a 

 leaf of the living Salisburia, and he will be struck with the 

 strong resemblance. The possibility of this has of course occurred 

 to those skilled botanists who have written on coal-plants ; but none 

 of them have, I think, been rash enough to call the Cyclopteris the 

 leaf of Dadoxylon, or to suggest, as I do now, that many of the leaves 

 called Noggeratliia, and even some called Adiantites are nothing more 

 or less than leaves of the coniferous trees, which we know abounded 

 in these old forests. 



It is otherwise with the fruit. Professor Henslow some time back 

 showed me the fruit of Salisburia, and compared it with the Trigono- 

 ca/rpon from the Manchester coal-sandstone. And Dr. Hooker, by a 

 scries of original researches into these coal-nuts (published in the 

 Royal Society's Transactions), has demonstrated that tbey are the 

 fruits or nuts of coniferous trees, each with a large fleshy envelope 

 like the fruit of the yew. Well then, if Dadoxylon is the common 

 fir-wood of the coal, and Trigonocarpwm the common coal fruit, we 

 need only put two and two together ; and if we cannot convince the 

 cautious botanists, I hope I may convince my student readers there 

 is a strong probability that the one is the fruit of the other. 



Coal pine-trees; coal pine-leaves, and coal pine-fruit! We are 

 getting on. Bu1 this is not quite all. The same distinguished 

 botanist to whom I have so often referred (who has shown us the 



