306 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 7, 



(Exogenous Gyvnnosperms.) 

 {Conifer ce.) 



2. Dadoxylon (Aeaucahites) Ouangondianum, Dawson. 



' Canad. Naturalist,' vol. vi. pp. 165, 166, figs. 1 to 4. 



** Branching trunhs, with distinct zones of growth, and a pith of the 

 Sternbergia type. Wood-cells very large, with three to five rows of 

 contiguous, alternate, hexagonal areoles ivith oval pores. Medul- 

 lary rays with one to three series of cells, and as many as 14 rows 

 of cells superimposed on each other*. '^ 



In sandstone at St. John, where many large trunks occur, calcified 

 and silicified, and in part converted into anthracite and graphite f. 

 My specimens are from the collection of Mr. Matthew, and are de- 

 scribed at length and figured in the paper referred to in the foot- 

 note. I have no doubt that this is the Coniferous tree referred to 

 by Dr. Gesner, ' Second Report,' p. 12. 



3. Dadoxylon Hallii, sp. nov. PI. XIII. fig. 11. 



Wood-cells very large, with five rows of contiguous, alternate, hexa- 

 gonal areoles. Medullary rays very frequent, and with as many as 

 thirty rows of cells superimposed. 



This species occurs in a pyritized state at Hemlock Creek, 

 Ontario County, New York, in beds of the Hamilton group. It 

 resembles D. Ouangondianum in the great size of the wood- cells 

 and the numerous rows of areoles, but differs so markedly in the 

 development of the medullary rays that I regard it as certainly be- 

 longing to a distinct species. The specimen, being completely pyri- 

 tized, can be examined only as an opaque object, so that some of the 

 details of its structure cannot be made out ; but the forms of the 

 wood-cells and their areoles, and of the medullary rays, are so 

 beautifully modelled in pyrites that no uncertainty exists as to the 

 points of structure above specified. I have dedicated this species to 

 Prof. Hall, its discoverer. 



4. Apoeoxylon. 



Among Prof. Hall's specimens is one, from Seneca Lake, which 

 may possibly be allied to the plant on which Unger has founded the 

 genus above named. It is a flattened pyritized stem or branch, one 

 inch and a quarter in breadth at the larger end, and slightly tapering, 

 and ten inches in length. It is marked with spirally arranged dis- 

 tant scars, as if of excurrent branches ; and it seems to have been 

 woody, with a thin bark and a large pith. The wood is imperfectly 



* In the case of this and other species described in my paper on the Pre- 

 carboniferous Flora of New Brunswick, I shall copy in this paper the specific 

 characters merely, referring for fuller descriptions to my paper in the ' Canadian 

 Naturalist,' vol. vi. pp. 161 etseq. 



t This and other fossil plants found at St. John afford remarkable examples 

 of the conversion of vegetable matter into graphite, without loss of its form or 

 even of its internal structure. 



