368 



PROCEEDINGS OF THE ACADEMY OF [July, 



The wood occurs in fragments of all sizes, up to complete trunks 

 a foot or more in diameter and several feet long. It is usually dark 

 brown in color, and almost entirely replaced by granular to minutely 

 crystalline quartz, 6 with occasional carbonaceous streaks. Its 

 original vegetable character is almost always evident to the naked 

 eye, although annual rings are never visible; and thin sections, 

 which are readily prepared by grinding with carborundum, after 

 the manner of making ordinary rock-sections, show under the micro- 

 scope every structural detail beautifully outlined in brown. While 

 usually found loose in the fields or along the roads, it has been ob- 

 served in place in several localities, and is always associated with 

 the highly arkosic sandstones or conglomerates which mark the 

 lower portions (Norristown or Stockton formation) of the Triassic. 

 It is not limited to any narrow horizon, however, but occurs at 

 various levels throughout a thickness of at least 5,000 feet of beds, 

 locality M. 1, for instance, being at the very base, and B. 3 at the 

 top, of that formation. 



The material found outside of Pennsylvania has all been referred 

 to three species, Araucarioxylon virginianum, A. woodworthi, and 

 ( '( droxylon huttonianum ?, the first being the most widely distributed. 

 As a result of the examination of some sixty specimens, about half 

 of which were sectioned by Mr. Vanartsdalen, two new species have 

 been recognized, which are here described as Araucarioxylon vanarts- 

 daleni and Brachyoxylon -pennsylvanianum. The present paper is 

 not to be regarded as the last word upon the subject, however, as it 

 is possible that the discovery of additional material may throw 

 further light on the status and relationships of these species. 



Genus ARAUCARIOXYLON Kraus. 



Araucarioxylon virginianum Knowlton. Plate III, figs. 1-3. 



Fossil Wood and Lignite of the Potomac [and Newark] Formation, Bull. 

 U. S. Geol. Surv., No. 56, pp. 50-52, pi. VII, 1889. A Revision of the 

 Genus Araucarioxylon of Kraus, Proc. U. S. Nat. Mus., XII, p. 615, 

 1889, and Amer. Jour. Sci., [3], XL, p. 257, 1890. Report on some Fossil 

 Wood from the Richmond Basin, Virginia, Ann. Rept. U. S. Geol. 

 Surv., XIX, pt. ii, pp. 516, 517, pi. LII, 1899. Description of a Small 

 Collection of Fossil Wood from the Triassic Area of North Carolina, 

 Ann. Kept. V. S. Geol. Surv. XX, pt, ii, pp. 272-274, pi. XXXVII, 1900. 

 Report on Fossil Wood from the Newark Formation of South Britain, 

 Conn. Ann. Rept, U. S. Geol. Surv., XXI, pt, hi, pp. 161, 162, 1901. 



Transverse Section: Annual ring indistinct; tracheids thick 



c Chemical analysis of a Lancaster County specimen (from L. 3) by Prof. 

 Miles Timlin, of the M illersville State Normal School, showed: Si0 2 , 96.5%; 

 1 '<■,<),, 1.2' , , the remainder being carbonaceous matter. Cf. PI. IV, fig. 6. 



