78 ROYAL SOCIETY OF CANADA 



In his Acadian Geology Sir William Dawson says further of the 

 trunks of this species, " they retain their structure in great perfection, 

 especially in silicified specimens. Some of the trunks have been a foot 

 or more in diameter. They show traces of growth rings on their wea- 

 thered ends, and when perfect are traversed by wrinkled pith cylinders 

 formally known as Sternbergiœ. Under the microscope the wood cells 

 are seen to be of remarkable size, being fully one-third larger in their 

 diameter than those of Pinus strohus or Araucaria Cunningliami, and 

 also much larger than those of the ordinary coniferous trees of the Coal- 

 measures. They are beautifully marked with contiguous hexagonal 

 aréoles, in which are inserted oval slits or pores, placed dia- 

 gonally. The medullary rays are large and frequent, but their 

 cells, unlike the wood cells (prosenchyma) are more small and 

 delicate than those of the trees just mentioned. The pith when perfectly 

 preserved presents a continuous cylinder of cellular tissue, wrinkled 

 longitudinally without, and transversely within, and giving forth intern- 

 ally delicate transverse partitions, which coalesce toward the centre, 

 leaving there a series of lenticular spaces, a peculiarity which I have not 

 heretofore observed in these Sternbergia pith cylinders. It was interest- 

 ing to find in a Devonian conifer the same structure of pith character- 

 istic of some of its allies in the Coal formation, where, however, as I have 

 elsewhere shown, such structures occur in Sigillaria as well; and since 

 Corda has ascertained a similar structure in Lomatofloyos, a plant allied 

 to TJlodendron, it would appear that the Sternbergiae may have belonged 

 to plants of very dissimilar organization. In my specimen the pith is 

 only half anj inch in diameter, and only a small portion of the wood is 

 attached to it; but Mr. Matthew has a specimen of a trunk ten inches in 

 diameter, with the pith one inch in thickness, and another eleven and a 

 half inches in diameter with the pith two and a half inches. Both had 

 the appearance of decayed trunks, so that their original size may have 

 been considerably greater." 



" Mr. Matthew states in reference to the mode of occurrence of this 

 interesting species, that the wood is always in the state of anthracite or 

 graphite, or mineralized by pyrites, calc spar or silica. The pith is 

 usually calcified, but in pyritized trunks it often appears as a sandstone 

 cast, with the external wrinkles of Sternbergia. The pith is often ex- 

 centric, and specimens occur with two or three centres ; but these consist 

 either of several trunks in juxtaposition, or are branching stems. The 

 annual layers vary from one-eighth i to one-thirtieth of an inch in thick- 

 ness, and adjoining layers sometimes vary from one-tenth i to one- 

 twentieth of an inch." 



1 I have not seen any so wide as this. — G. F. M 



