1865.] DAWSON COAL-rOBMATION. 139 



The species of LepidopMoios are readily distinguished from Lepi- 

 dodendron by the form of the areoles, and by the round scars on the 

 stem, which usually mark the insertion of the strobiles, though in 

 barren stems they may also have produced branches ; still the fact of 

 my finding the strobiles in situ in one instance, the accurate resem- 

 blance which the scars bear to those left by the cones of the Red Pine 

 when borne on thick branches, and the actual impressions of the 

 radiating scales in some specimens, leave no doubt in my mind that 

 they are usually the marks of cones ; and the great size of the cones 

 of Lepidopliloios accords with this conclusion. 



The species of LepidopMoios are numerous, and individuals arc 

 quite abundant in the Coal-formation, especially toward its upper 

 part. Their flattened bark is frequent in the coal-beds and their 

 roofs, affording a thin layer of pure coal, which sometimes shows the 

 peculiar laminated or scaly character of the bark when other charac- 

 ters are almost entirely obliterated. The leaves also are nearly as 

 abundant as those of SigUlaria in the coal-shales. They can readily 

 be distinguished by their strong angular midrib. 



I figure, in illustration of the genus, all the parts known to mo of' 

 L. Acadianus, and characteristic specimens of other species. One of 

 these, L. parvus, is characteristic of the Upper Coal-formation. ( Vide 

 Plate X. & Plate XI. fig. 51.) 



11. Cordaites or Pijchnophyllum. — This plant is represented in the 

 Coal-formation chiefly by its broad striated leaves, which are 

 extremely abundant in the coal and its associated shales. Some 

 thin coals are indeed almost entirely composed of them. The most 

 common species is O. horassi folia, a plant which Corda has shown to 

 have a simple stem with a slender axis of scalariform vessels resem- 

 bling that of Lepidophloios ; for this reason, notwithstanding the 

 broad and parallel-veined leaves, I regard this genus as belonging 

 to Lycopodiacece or some allied family. It must have been extremely 

 abundant in the Carboniferous swamps ; and, from the frequency of 

 its being covered with Spirorlis, I think it must either have been of 

 more aquatic habit than most of the other plants of the Coal-forma- 

 tion, or that its leaves must have been very durable. While the 

 leaves are abundant, the stems are very rare. I infer that they were 

 usually low and succulent. Much of the tissue found in the coal, 

 which I have called "epidermal," probably belongs to leaves of 

 Cordaites. 



In the Upper Coal-formation there is a second species, distinguished 

 by its simple and uniform venation. This I have named G. sim- 

 plex. 



12. Sporangites. — To avoid the confusion which envelopes the clas- 

 sification of Carpolites, I have used the above name for rounded spore- 

 cases of Lepidodendron and allied plants, which are very frequent 

 in the coal. A smooth round species like a mustard- seed, is exces- 

 sively abundant in the Lower Carboniferous at Horton, and probably 

 belongs to Lejndodendron corrugatum, with which it is associated. 

 A species covered with papillee, S. papiUata, constitutes nearly the 

 whole of some layers in coal 12, group xix, of the preceding Section. 



