V °188" 1 '] PROCEEDINGS OF THE NATIONAL MUSEUM. 615 



2. Araucarioxylon Edvardianum Dn. Sp. 



Dadoxylon Edvardianum Dawson. Rept. on Geol. Struct and Mineral Resources 

 of Prince Edward Island ; Montreal, 1871, p. 45, PL III, figs. 25-27. 



Trunks without distinct rings of growth, and with a central Pith not 

 observed to have transverse lainiure. Wood cells with one, or rarely 

 two, of contiguous hexagonal areoles. Medullary rays simple, infre- 

 quent, with two to ten rows of cells superimposed. 



Habitat. — Triassic, Prince Edward Island. 



3. Araucarioxylon Wurtembergiacum Kraus. 



Schimp. Pal. Veg. H, p. 384. 



Pinites Wiirtembtrgiacus Goppert. Monog. d. Foss. Conif., 1850, p. 212. 



Concentric circles (nearly 10 mm broad) indistinct; trachei'ds equal, nar- 

 row, thick walled, provided with a single series of small contiguous 

 pores; medullary numerous, composed of one to ten superimposed cells. 



Habitat. — Jurassic formation, near Wiirtemberg and Waidhofen. 



4. Araucarioxylon Virginianum Knowlton. 



Fossil Wood and Lignites of the Potomac Formation, Bull. U.S. Geological Survey, 

 No. 56, p. 50, PI. vii, figs. 1-4. 



Annual ring very indistinct, about 2 mm broad ; trachei'ds bearing one 

 to two rows of hexagonal pits on the radial walls, mudullary rays simple; 

 of one to twenty-seven superimposed cells ; resin ducts none. 



Habitat. — Potomac Formation, Taylorsville, Virginia. 



5. Araucarioxylon Argilliacola Eichw. Sp. 



Araucarites ArgiUicola Eichwald. Letluea Rossica, Vol. n, 1865, p. 51, PI. v, 

 figs. 12-12c. 



Concentric circle indistinct; tracheids quadrate-ovate in section, 

 small, thick-walled, provided with two, rarely three, series of angular 

 pores ; medullary rays provided with small pores. 



Habitat. — Russia. 



6. Araucarioxylon Doeringii Conwentz. 



Sobre Algnnos firboles Fosiles del Rio Negro. Boletin de la Acad. Nacional d. 

 Cienc. en Cordoba, Vol. VII, 1885, p. 448. 



Concentric circles distinct, broad, the exterior zone narrower; trach- 

 ei'ds provided with a single series of contiguous or with two series of 

 alternate pores ; medullary rays composed sometimes of a single series 

 of from one to sixteen superimposed cells, sometimes of two series of 

 from five to forty cells. 



Habitat. — Rio Negro, South America. (Suboligocene.) 



