430 THE CARBONIFEROUS SYSTEM. 



similar character in a perfectly mineralized condition, 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 

 SternbergifE, in connexion with their state of preservation, seems to 

 strengthen a conclusion at which I have been arriving from micros- 

 copic and field examinations of the coal and carbonaceous shales, that 

 the thickest beds of coal, at least in Eastern America, consist in great 

 part of the flattened bark of coniferous, sigillarioid, and lepidodendroid 

 trees, the wood of which has perished by slow decay, or appears only 

 in the state of fragments and films of mineral charcoal. This subject, 

 however, will be introduced in the next section of this chapter. In 

 my researches in microscopic coal structures, I have also ascertained 

 that some Sternbergije are pith cylinders of Sigillarije. (Fig. 

 161, M). 



The most abundant locality of Sternbergia with which I am 

 acquainted occurs in the neighbourhood of the town of Pictou, im- 

 mediately below the bed of erect calamites described in the Journal of 

 the Geological Society (vol. yii., p. 194). The fossils are found in 

 interrupted beds of very coarse sandstone, with calcareous concretions, 

 imbedded in a thick reddish brown sandstone. These gray patches 

 are full of well-preserved Calamites, which have either grown upon 

 them, or have been drifted in clumps with their roots entire. The 

 appearances suggest the idea of patches of gray sand rising from a 

 bottom of red mud, with clumps of growing Calamites which arrested 

 quantities of drift plants, consisting principally of Sternbergia and 

 fragments of much decayed wood and bark, now in the state of coaly 

 matter, too much penetrated by iron pyrites to show its structure dis- 

 tinctly. We thus probably have the fresh growing Calamites entombed 

 along with the debris of the old decaying conifers of some neighbour- 

 ing shore ; furnishing an illustration of the truth, that the most 

 ephemeral and perishable forms may be fossilized and preserved con- 

 temporaneously with the decay of the most durable tissues. The rush 

 of a single summer may be preserved with its minutest striae unharmed, 

 when the giant pine of centuries has crumbled into dust or disappeared. 



2. Sigillariacece or Sigillarioid Trees. 



1. Genus Sigillaria. — The Sigillaria^, so named from the seal-like 

 scars of fallen leaves stamped on their bark, were the most important 

 of all the trees of the coal- swamps, and those which contributed most 



I 



