68 



still more external, consists of bast and other tissues; next, we have 

 a large area of inn®r cortex which is oniy preserved in part, and 

 finally the outer cort«x, in places broken away from the rest. The 

 latter shows several radially arranged gaps through which the 

 leaf-traces pass out into the leaves. From the South Lancashire 

 coalfield. X 2. This and other photographs should be examined 

 with a hand-lens. 



Page 12. A transverse section of a petrified Lepidodendroid stem 

 showing another type of internal structure, and one common to botb 

 Lepidodendron and Lepidophloies. In the centre there is a pith, 

 and the narrow light-coloured ring surrounding it is the primary 

 wood. More externally a broader, very dark ting of bast and other 

 tissues is conspicuous. Next, the still broader ring of the inner 

 cortex, in which several leaf-traces are to be seen. The middle 

 cortex is not well preserved, an empty space between the inner and 

 the outer cortex marking its position. From the S. Lancashire 

 coalfield. X a^. 



Page 13. Lepidostrobus. A cone belonging to Lepidodendron. 

 The cones were long and consist of crowded, spii ally-arranged sporo- 

 phylls or leaves bearing sporangia. In this specimen the^ cone 

 is split almost through the middle, and the axis can be seen in the 

 upper part. At the margin the upturned edges of the sporophylls 

 can be made out. Some of the darker, obliquely-directed markings 

 between the axis and the margins are the sporangia, which were 

 long, and attached one to the upper surface of each sporophyll. 

 From the South Lancashire coalfield. Reduced, f natural size. 



LEPIDOPHLOIOS. 



Page 14. Lepidophloios laricinus, Sternberg.* Lepidophloios 

 differs from Lepidodendron in the shape of the leaf-bases, which are 

 diamond shaped and scale-like, overlapping one another. The leaf- 

 scar is also broader than long, and, in older stems like the present 

 specimen, is situated at the bottom of the leaf base. From the 

 Yorkshire coalfield. Natural size. 



Page 15. Halonia. A branch of a Z.<?/zV<?/>^/<7/^j bearing large, 

 spirally-arranged tubercles, which are generally believed to be the 

 broken bases of the stalks of cones of the Lepidostrobus type. The 

 leaf-scars between the tubercles are badly preserved in this example. 

 From the Yorkshire coalfield, f natural size. 



BOTHRODENDRON. 



Page 16. Bothrodendron punctatum, Lindley & Hutton.* 

 The stems of this genus bore widely separated leaves, the bases of 

 which were not enlarged. The oval leaf-scars, the actual points 

 of attachment of the leaves, are small, and the bark between them 

 is ornamented by a network of fine strise. From the Yorkshire 

 coalfield. X f . 



SIGILLARIA. 



The stems of some Sigillarias v/ere ribbed, while others did not 

 possess ribs. These stems are distinguished from those of Lepi' 

 dodendron and Lepidophloios by the fact that the leaf-scars are 

 arranged in vertical rows, those of one row alternating in position 

 with the scars of the adjacent rows on either side. 



