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I 



Ij 



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16 canadian fossils. 



Genus Prototaxites — Dn. '' ' ' 



6. — Prototaxites Looani,— Dn. (PI. II, Figa. 18 to 27.)— J. G. S. 

 XV, 484; Fig. 4. Report of Geological Survey of Canada, 401 ; Fig. 

 430.— L. & M.D., Canada. 



" Woody and branching trunks, with concentric rings of growth and med- 

 ullary rays, (jells of pleurenc/u/ma not in regular lines, cylin- 

 drical, thick-walled, with a double series of spiral fibres. Discs 

 or bordered pores feio, circular and indistinct. The specimens are 

 usually silicified, with the bark in a coaly state." 



This species was described, and the genus Prototaxites established, on 

 the evidence of specim* collected by Sir W. E. Logan, and of a trunk 

 eighteen inches in diameter observed by me in Gaspd on my first visit. In my 

 more recent visit, I was so fortunate as to find two additional trunks 

 imbedded in the sandstones. One was about two feet in diameter, and with 

 seven feet of its length exposed. The other was not less than three feet 

 in diameter and of unknown length, only a few feet of the larger end 

 having been uncovered. Both were prostrate and silicified. In addition 

 to these we found at Little Gasp(5, near the junction of the Gasp^ sand- 

 stone with the Upper Silurian limestone, two stumps of trees of this spe- 

 cies, with spreading roots. As they did not appear to be imbedded in 

 an underclay, but in the ordinary sandston^, I suppose them to have been 

 drifted stumps. They are, however, of importance as shewing the exis- 

 tence of these trees at the beginning of the Devonian period, and also as 

 proving that the roots were similar in form and structure to the stem, 

 and of woody character. Loose fragments of the silicified and carbonized 

 wood of Prototaxites, recognizable by its structure under the microscope, 

 were also found in several places, and specimens were obtained by Prof. 

 Bell, of the Geological Survey, in places not visited by me. These facts 

 show that these trees are by no means rare ; and they occur under pre- 

 cisely the same conditions with the drifted trunks of Coniferous trees found 

 in the sandstones of the coal formation. This mode of occurrence, as 

 compared with that of Siigmarice, Lepidodendra, &c., in the same beds, 

 shows that the wood of Prototaxites must have been comparable to that 

 of ordinary Coniferous trees in durability, lightness, and resistance to 

 water soakage. Two of the larger trunks we found are represented in 

 situ, in the wood-cuts. ' 



Though all the trunks hitherto found are silicified, and dark in colour 

 except when stained with ferruginous matters, they differ very much in 

 their state of preservation. In some cases the wood appears as a homoge- 



