EASTERN BORDERS. 301 



of Lepidodendron ; it consisted principally of soft cellular tissue ; 

 between a broadish cellular columa and a double cellular zone was 

 interposed a narrow vascular cylinder, and on the exterior was a thin 

 cuticle or bark. The structure generally both of the stem and fruit, 

 and the mode of branching bring the Lepidodendrons into near affinity 

 to the Lycopodium, but the structure of the vascular cylinder and 

 the appearance of fistular passages in the bark indicate at least a 

 distant relationship to Coniferee. They were succulent, yet lofty 

 trees, resembling in magnitude and appearance those Araucarias 

 which are clothed with an imbricated foliage. 



The determination of the species is difficult and sometimes impos- 

 sible, because the markings on the stem may be different in the 

 young state from that in the old, and because, moreover, the fossil 

 may present an impression or cast either of the outer or of the inner 

 surface of the bark. Further inquiry will probably reduce the 

 number of species already described. The following have been found 

 in our district: — 



Lepidodendron Harcourtii (With.). Ref. Trans. Nat. Hist. 

 Soc. of Northd. vol. ii. pi. 5, 6. 



Localities. Hesley Heath near Rothbury, Alnwick Moor. 



Lepidodendron obovatum (Sternb.). Ref. Stemb. t. 6. f. 1. 



Locality. Near Spittal, in sandstone, on the authority of Mr. 

 Winch. 



Lepidodendron aculeatum (Stemb.). Ref. Sternb. t. 6. f. 1. 



Localities. Howick and North Sunderland, in sandstone and shale. 

 This species has not, so far as we know, been found in the upper coal- 

 measures of England ; it seems to belong more particularly to (he 

 Mountain Limestone series. 



Lepidodendron Sternbergii (Brong.). Ref. Foss. Fl. t. 4. 

 Locality. Alnwick Moor and Howick, in sandstone. 



Lepidodendron Selaginoides (Lindl.). Ref. Foss. Fl. t. 12. 



Locality. Barmoor, in a carbonaceous shale above the coal. The 

 specimen is a portion of a large stem ; the form of the scars is 

 narrow, and agrees pretty nearly with Lindley and Hutton's figure. 



Lepidodendron gracile (Brong.). Ref. Brong. Hist. t. 15. 



Locality. Alnwick Moor, in shale above the coal, along with Avi- 

 cula Verneuilii (M'Coy) and other marine shells. The specimen 

 is dichotomose, and possesses a central column, passing through 

 the stem and up the branches, retaining structure. 



Lepidodendron anglicum (Sternb.). Ref. Sternb. t, 29. f. 3. 

 Locality. Howick, in sandstone. 



