164 THE GEOLOGICAL HISTORY OF PLANTS. 



the leaf -bases prominent, or have an appearance of longitudinal rib- 

 bing produced by the expansion of the bark. 



Structure of Stem. — This is not perfectly preserved in any of 

 my specimens, but one flattened specimen shows a central medulla 

 with a narrow ring of scalariform vessels surrounding it, and consti- 

 tuting the woody axis. The structure is thus similar to that of L. 

 Harcourtii, which I regard as probably the same with the closely 

 allied European species L. Veltheimianum. 



Leaves. — These are narrow, one-nerved, curving somewhat rap- 

 idly outward (Figs. 43, B, C, D). They vary from one to two inches 

 in length. 



Hoots. — I have not seen these actually attached, but they occur 

 very abundantly in the underclays of some erect forests of these 

 plants at Horton Bluff, and are of the character of Stigmarice (Figs. 

 30, 31). In some of the underclays the long, flattened rootlets are ex- 

 cessively abundant, and show the mark of a central vascular bundle. 



Fructification. — Cones terminal, short, with many small, acute 

 imbricate scales. Spore-cases globular, smooth (Fig. 43 C). On 

 the surface of some shales and sandstones at Horton there are innu- 

 merable round spore-cases of this tree about the size of mustard-seed 

 (Fig. 43 F). Large slabs are sometimes covered with these, and thin 

 layers of shale are filled with flattened specimens. 



This is the characteristic species of the Lower Carboniferous coal- 

 measures, occurring in great profusion at Horton Bluff and its 

 vicinity, also at Sneid's Mills near Windsor, Noel and Five-Mile 

 River, at Norton Creek and elsewhere in New Brunswick (Matthew's 

 collection), and at Antigonish (Honey man's collection). 



I have received from the lowest Carboniferous beds of Ohio speci- 

 mens of this species.* According to Rogers and Lesquereux similar 

 forms occur in the Vespertine of Pennsylvania and in the Lower 

 Carboniferous of Illinois. L. Veltheimianum of western Europe 

 and L. glincanum of Russia are closely allied Lower Carboniferous 

 species, f 



A very different type is furnished by a new species from the 

 middle coal-formation of Clifton, New Brunswick. 



Lepidodendron Cliftonense, Dawson. — Habit of Growth. — 

 Robust, with thick branches, and leaves several inches in length. 

 Terminal branches becoming slender, with shorter leaves. 



* "Journal of Geological Society," November, 1862, p. 313. 

 f For comparisons of these see " Report on Plants of Lower Carbon- 

 iferous of Canada," p. 21. 



