140 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [DoC. 20, 



I have no indication as to the plant to which it may belong, except 

 that it is associated with Cordaites. (Figs. 80 & 81, PI. XII.)* 



13. Tissues in the Mineral Charcoal. — On these I have little to add 

 to the statements in my paper of 1859, " On the Yegetable Structures 

 in CoaP't. These tissues may he arranged as follows : — 



a. Bast tissue, or elongated cells from the liber or inner hark of 

 Sigillarise and Lepidodendron, hut especially of the former. — This 

 kind of tissue is abundant in a calcified state in the shales associated 

 with the coals, and also as mineral charcoal in the coals themselves, 

 and in the interior of erect Sigillarice. It is the kind of tissue 

 figured by Brongniart as the inner layer of bark in Sigillaria 

 elegans, and very well described by Binney (Quart. Journ. Geol. Soc. 

 vol. xviii.) as " elongated tissue or utricles." Under the microscope 

 many specimens of it closely resemble the imperfect bast tissue of 

 the inner bark of Pinus strohus and Thuja occidentalis ; and like this 

 it seems to have been at once tough and durable, remaining in 

 fibrous strips after the woody tissues had decayed. It is extremely 

 abundant at the Joggins in the mineral charcoal of the smaller 

 coal-seams. It is often associated with films of structureless coal, 

 which represent the dense cellular outer bark which, in the trunk 

 of SigiUaria, not only surrounded this tissue, but was intermixed with 

 it. (Pig. Q2, PL XII.) 



b. Vascular hundles of Ferns. — These may be noticed by all close 

 observers of the surfaces of coal, as slender hair-like fibres, some- 

 times-lying separately, in other cases grouped in bands half an inch or 

 more in diameter, and imbedded in a loose sort of mineral charcoal. 

 When treated with nitric acid, each bundle resolves itself into a few 

 scalariform vessels surrounded with a sheath of woody fibres, often 

 minutely porous. This structure is precisely that of macerated fern- 

 stipes ; but, as already stated, there may have been some other coal- 

 plants whose leaves presented similar bundles. As stated in my for- 

 mer paper " On the Vegetable Structures in Coal," this kind of tissue 

 is especially abundant in the coarse and laminated portions of the 

 coal, which we know on other evidence to have been made up, not 

 of trunks of trees, but of mixed herbaceous matters. (PL XII. 

 fig. 67.) 



c. Scalariform vessels.^— T\iq^q are very abundant in the mineral 

 charcoal, though the coarser kinds have been crushed and broken in 

 such a manner that they usually appear as mere debris. The sca- 

 lariform vessels of Lepidodendron, Lepidophloios, and Stigmaria are 

 very coarse and much resemble each other. Those of ferns are 

 finer, and sometimes have a reticulated structure. Those of Sigil- 

 laria are much fiuer and often have the aspect of wood-cells with 

 transversely elongated pores like those of Cycas. Good examples of 

 these are figured in the paper already referred to. (See also Plate 

 XI. figs. 54, &c.) 



d. Discigerous luood-cells. — These are the true bordered pons 



* It much resembles the spore-cases of Fhmingites gracilis, as figured by Car- 

 rulhers, ' Gcol. Mag.' vol. ii. I suppose this to be a strobile of Lejpidophloio?. 

 t Quart. Journ. Geol. Soc. Tebruary 18G0. 



