OF LOWER GKKJSySAXJ) PLANTS. 195 



V. 11847 a-V. 11847 c cub from it; British Museum (Nat. 

 Hist.). 



DESCRIPTION. Four large specimens and some smaller splints 

 of wood were found near together, and possibly form part of a 

 large trunk. One of the pieces was cut, and the species is 

 described from sections, cut from this block, roughly measuring 

 9 x 10 x 12 cm., including only secondary wood. The woody 

 texture is apparent on the external surfaces of the specimen, and 

 the grain is very gnarled and knotty. The infiltration of the 

 petrifying medium has been irregular, so that the large masses 

 tend to split up. The whitish mass of the fossil is in parts very 

 much iron-stained. Another specimen in the older collections 

 of the Museum (V. 5659) appears to be identical, in all essen- 

 tials, with this species. 



TOFOGKAPHY OF THE STEM. Secondary wood only is preserved. 

 In this the growth-rings are well marked. The number of ele- 

 ments comprising a ring varies greatly, running up to 200 in 

 radial series, the maximum thickness of a year's growth being 

 as much as 8 mm. The autumn wood is very small in amount, 

 consisting of only 3-5 narrow elements, whose walls are not 

 excessively thickened. The wood is uniform, the elements large 

 and squarish, adjacent elements often being on the same tangent. 

 Resin-canals are entirely absent. Resin-containing wood-paren- 

 chyma is scattered all through the wood. 



The medullary rays are the salient feature of this species, 

 and are very remarkable for a Conifer. They are exceedingly 

 numerous, and most are bi- or multiseriate in part (PI. XV 111, 

 fig. 2). The rays are often 1 tracheid distant, and seldom more 

 than 4 tracheids distant, in which case it is only for a short 

 vertical course, for they quickly approach another ray only 

 1 or 2 tracheids away. The photo. (PL XVIII, fig. 2) illustrates 

 this extraordinary ray-structure very well. That it is normal 

 for this wood seems proved by the nature of the specimens from 

 which the sections were cut; good-sized sections were taken 

 from a mass of petrified wood of such a size as to indicate that 

 it was part of a tree-trunk of many years' growth. The very 

 low rays of 1-3 cells high, so common in the majority of 

 Coniferse mingled with taller rays, are in this fossil absent 

 in parts of the wood, where uniseriate up to multiseriate rays 

 as much as 70-80 cells high are common. 



o2 



