1855.] On the age of the Coal strata in Central India. 351 



erroneously so-called, correspond exactly with the JBhyllothecas of 

 Central India. And if we are to count the strata of Mangali 

 among the representatives of our carbonaceous shales, then they 

 furnish other two points of comparison with the Richmond coal 

 basin, viz. in a Knorria, and another stem, resembling a Lepidoden- 

 dron, but which may be called an aphyllum or perhaps Aspidiaria* 

 I might here add a third link of connexion between those Mangali 

 and Richmond beds, viz. the occurrence of two forms of Entomos- 

 traca belonging to the genus JEstheria. But in this instance, the 

 evidence of the Fossil Fauna is not so distinct as that of the ancient 

 Flora. The inference to be drawn from a particular species of 

 Tceniopteris being common to the rocks of Eastern Virginia and 

 Central India is, in my opinion, conclusive as to their contempora- 

 neousness ; but not so that drawn from the discovery of Estheria ' 

 in both, as the genus just named, after having been too frequently 

 taken for a mollusc, is now recognised in the carboniferous forma- 

 tion, and, I believe, the old red sandstone, as well as in the Lias, 

 the Oolite, and the "Wealden. Judging from Sir C. Ly ell's figure, 

 there is a great agreement between his species and ours, but when 

 Rupert Jones, one of our best authorities in this department, is 

 able to pronounce upon them, his decision will set the matter 

 at rest. 



I suspect that a good many other instances of resemblance be- 

 tween our fossil plants and those of admitted Jurassic strata might 

 be pointed out ; but materials as yet are deficient. There is still 

 wanting a revision of our ancient flora, discriminating between 

 true Carboniferous and Oolitic types. For example, how long have 

 all furrowed stems in Europe and America, and I need not add 

 India also, been referred to Catamites and more rarely TZquisetum, 

 whereas many of them, viz. those characterized by the absence of 

 tubercles, and the opposite arrangement of their sulci, must un- 

 doubtedly be classed under the genus Phyllotheca. To establish some 

 such clear distinction as this, is a step towards the determination 

 of the age of the rocks, in which those stems are respectively met 

 with ; while an alternate furrowed tuberculated stem is never found 

 in the Oolite, on the other hand, the stems destitute of tubercles 

 and with opposite sulcation almost exclusively occur in that forma- 

 tion. 



