464 Dr. H. Woodward — Carboniferous Arthropods. 



sixty-eight different levels. Like the seams of coal which often 

 cover them, these root-beds, or old soils, are at present the most 

 destructible masses in the whole cliff, the sandstones and laminated 

 shales being barder and more capable of resisting the action of the 

 waves and the weather. Originally the reverse was doubtless true, 

 for in the existing delta of the Mississippi those clays in which the 

 innumerable roots of the deciduous cypress and other swamp-trees 

 ramify in all directions are seen to withstand far more effectually 

 the undermining power of the river, or of the sea at the hase of the 

 delta, than do beds of loose sand or layers of mud not supporting 

 trees. 



As regards the fossil plants (of which Sir William Dawson records 

 over 150 species in the Coal-measures of the South Joggins),^ they 

 belong to the same genera, and most of them to the same species, as 

 those met with in the distant coal-fields of Europe. Many of the 

 still erect trunks of Sigillaria and Lepidodendron had their interiors 

 filled up with layers of sandstone, in which Lyell frequently observed 

 fern-leaves, and sometimes fragments of Stigmaria, which had 

 evidently entered together with sediment after the trunk had 

 decayed and become hollow, while still standing under water. 



When the Carboniferous forests sank below high-water mark 

 a species of Spirorhis or Serpula attached itself to the outside of the 

 stumps and stems of the erect trees, adhering occasionally even to 

 the interior of the bark — another proof that the process of envelop- 

 ment was very gradual. These hollow upright trees, covered with 

 innumerable marine annelids, resemble a "cane-brake", as it is 

 commonly called, consisting of toWreQdiS, oi Arundinaria macrosperma, 

 which Lyell saw in 1846, at the Balize, or extremity of the delta of 

 the Mississippi. Although these reeds are freshwater plants they 

 were covered with Balani, having been killed by an incursion of 

 salt water over an extent of many acres, where the sea had for a 

 season usurped a space previously gained from it by the river. Yet 

 the dead reeds, in spite of this change, remained standing in the 

 soft mud, showing how easily the Sigillarice and Lepidodendron, 

 hollow as they were but supported by strong roots, may have 

 resisted for some time an incursion of the sea. 



The investigation of the organisms preserved in the interior of 

 these hollow trunks of Sigillarice, at the Joggins Coal-measures, by 

 Sir William Dawson, during many years, has resulted in the further 

 discovery of quite a number of new and very interesting forms of 

 terrestrial animals belonging to the Coal period. 



Of these we ma}^ mention the remains of some small Amphibian 

 reptiles referred to Dendrerpeton Acadiamim and Hylonomus Lyelli, 

 Dawson. To these have been added Baphetes planiceps ; numerous 

 insect remains, and a Myriopod, Xylolius sigillarics; an air-breathing 

 snail, Pu2}a vetusta, etc' 



^ Acadian Geology : The Geological Structure, Organic Bemains, and 

 Mineral Resources of Nova Scotia, Neiu Brunswick, and Prince Edxoard 

 Island, by Sir Wm. Dawson, 8vo, 1868, pp. 694. 



° "Air-breathing Animals of the PalEeozoic Eoeks in Canada," by Sir Wm. 

 Dawson, C.M.G., F.E.S. : Trans. Eoy. Soc. Canada, 1894. 



