100 



THE GEOLOGIST. 



A LECTURE ON "COAL." 

 By J. W. Salter, F.G.S. 

 (Continued from page 68.) 



We finished last month with the fact that plant-remains were fonnd 

 in plenty both above and below the coal. I shall draw your attention 

 first to the roof-shale — or clay over the coal — " over-clay" as it is often 

 called : for in this the great majority of remains are preserved. 



In the roof-shale two kinds of plants are the most conspicuous — : 

 fern-leaves, and the diapered cylinders mentioned in our last. These 

 are the prevailing fossils, though there are a great many besides. 



Looking first at the fern-leaves, which from their beautiful forms 

 cannot fail to strike the observer's eye, one is surprised to notice the 

 extremely perfect state in which they occur. Delicate fronds, spread 

 out as for the sheets of an herbarium, with hardly a leaflet disturbed 

 from its true place, crowd the roof-shales of nearly all coal-mines. 



Dr. Buckland sang the praises of this beau- 

 tiful tracery, which covers the roof of the 

 mine, in glowing strains such as it will 

 not do for a plain geologist to imitate. I 

 have a lurking suspicion, however, that the 

 great doctor conceived the passage not in 

 the mine, but out of it. 



At least one hundred and twenty species 

 are known in our British coal-strata. So 

 perfect are they occasionally, that the little 

 fruit-patches (sori, as botanists term them), 

 are found upon the backs of the fronds. This 

 is not very common, except in one kind — 

 the Pecopteris, which happens to be more 

 abundant than most of the others, and in 

 some species of this the fruit is found. 

 There is a specimen in the Museum of 

 Practical Geology which shows these little 

 seed-patches. It is from the Forest of Dean ; 

 and Mr. Gr. Roberts has shown me several, 

 and given me some from the coal-field of 

 Bewdley Forest. We shall give a figure of 

 this fruit in our next number. 



Some ferns nay, many of them remind 

 ihovterk (Pecqpteris) Um- ns closely oi the tree-terns laminar m our 

 e«tfea.-krong. hot-houses: others resemble the humble 



* Those who really wish to know more about coal-plants than this little sketch 

 will give them, should read the article on coal in the new edition of Mantell's 

 " Woiubrs of Geology." By T. Rupert Jones, Esq., of the Geol. Society. 



