36 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 2, 



laminated argillaceous sandstone. It is finely ribbed with distant 

 joints, and its lower part is somewhat compressed, probably because 

 imperfectly filled with sediment. The stem a gives off the stem h, the 

 bark or coaly investment being thickened at the junction of the stems. 

 The stem h rapidly increases in thickness, and at its fifth joint gives 

 off the third stem c, which at first diverges from it nearly at right 

 angles. Stem « is 1 inch in diameter. Stem h at the distance of 

 2 inches from the junction is 1^ inch in diameter. Stem c at 

 2 inches from its origin is more than 2 inches in diameter. The ribs 

 of h and c are wider and shorter than those of a, those of c being 

 the widest. See fig. 1 2, a', c', by which it will be observed that the 

 stems a, «', and c, c', though proceeding from the same root, are so 

 different that they might be mistaken for distinct species. 



All the erect Calamites exist as stony casts generally cylindrical, 

 but when they have been imperfectly filled with sediment the spaces 

 between the joints have given way to lateral pressure, as represented 

 in fig. 15. I mention this here, because these compressed portions 

 of the stem are liable to be mistaken for the base of the plant. 



The leaves of the Calamite are but rarely attached to the stems. 

 They are verticillate, linear, pointed, and delicately striated (fig. 16). 

 They are either straight and horizontal, or slightly curved downward. 

 In decay their extremities drooped into a vertical position, the basal 

 portion still projecting horizontally. 



Calamites formed dense and tall jungles or brakes, and sometimes 

 flourished as an undergrowth in Sigillaria- woods. The greatest 

 distance to which I have traced one of the Calamite brakes is in the 

 case of that which occurs about 18 feet over the main coal. In a 

 new shaft sunk about half a mile inland, this bed is found to abound 

 in erect Calamites just as in the cliff, and the fresh unweathered 

 specimens from this shaft displayed the attached leaves much better 

 than those from the cliff. 



4. Poacites. — These broad striated leaves are very abundant, not 

 only in the Joggins section, but in all parts of the Coal formation of 

 Nova Scotia, and even in the Lower Carboniferous rocks. They are 

 occasionally seen to terminate in blunt points, but I have found no 

 specimen with either petiole or stem. Straight or branching stems, 

 with striation similar to that of these leaves, are, it is true, occasionally 

 found in the same beds, but they may have belonged to Ferns. The 

 largest specimen that I have seen is in the collection of Henry Poole, 

 Esq., of the Albion Mines, Pictou. It is 1 8|- inches in leiigth, 5 inches 

 wide at the larger end, and \-^^ inch at the smaller, where it is broken 

 off. It has delicate longitudinal strise, a sort of thickened midrib, 

 and waves or sharp flexures of the striae proceeding from the midrib 

 to the edges, and probably marking undulations of the recent leaf, 

 which must have given it a very graceful appearance. Smaller 

 specimens, however, usually want the midrib and waving lines. 



5. Artisia. — The casts of medullary cavities known by this name* 



* [See also Professor Williamson's paper " On the Structure and Affinities of the 

 Plants hitherto known as Sfei-nbergicp;" Manchester Lit. Phil. See. 1851, vol. ix.] 



