304 SternhergicB. 



frequently, only fragments of the wood remain, in such a condi- 

 tion as to evidence an advanced state of decay ; whi^e the bark- 

 like medullary lining remains. In other specimens the coaly 

 coating investing the cast, sends forth flat expansions on 

 either side, as if the sternhergia had been the mid-rib of a long 

 thick leaf. This appearance, at one time very perplexing to me, 

 I suppose to result from the entire removal of the wood by decay, 

 and the flattening of the bark, so that a perfectly flattened soeci- 

 men, like that in Fig. 6, may be all that remains of a coniferous 

 branch nearly two inches in diameter. A still greater amount of 

 decay of woody tissue is evidenced by those sternbergia casts 

 v,'hich are thinly coated with structureless coal. These must, in 

 many cases, represent trunks and branches which have lost their 

 bark and w^ood b};- decay ; while the tough, cork-like, chambered 

 pith drifted away to be imbedded in a separate state. This might 

 readily happen with the pith of Cecropia ; and perhaps that of 

 these coniferous trees may have been more durable ; while the 

 wood, like the sap wood of many modern pines, may. have been 

 susceptible of rapid decay, and liable, when exposed to alternate 

 moisture and dryness, to break up into those rectangular blocks, 

 which are seen in the decaying trunks of modern conifers, and 

 are so abundantly scattered ovef the surfaces of coal and its asso- 

 ciated beds in the form of mineral charcoal. 



Some specimens of sternbergia appear to show that they have 

 existed in the interior of trxrnks of considerable size. The best in- 

 stance of this that I have found is that represented in Fig. 7, from 

 the South Joggins, and which appears to show the remains of a 

 tree a foot in diameter, now flattened and converted into coal, 

 but retaining a distinct cast of a wrinkled sternbergia pith. 



Are we to infer from these facts that the wood of the trees of 

 the genus Dadoxylon was necessarily of a lax and perishable tex- 

 ture. Ifs structure, and the occurrence of the heart wood of huge 

 trunks of similar character in a perfectly mineralized condi- 

 tion, would lead to a different conclusion ; and I suspect that 

 we should rather regard the mode of occurrence of sternbergia 

 as a caution against the too general inference from the state 

 of preservation of trees of the coal formation, that their 

 tissues were very destructible, and that the beds of coal must 

 consist of such perishable materials. The coniferous character of 

 the sternbergise, in connection with their state of preservation, 

 seems to strengthen a conclusion at Avhich I have been arriving 



