142 



but narrower at and near the base and apex, and apparently flattened, 

 with no indications of a central axis or virgula. Lateral ramifications 

 simple, unbranched, narrower than the rhachis, averaging about one 

 millimetre apart, the longest about fifteen mm. in length, divergent in 

 the same plane outward and a little upward, but showing no traces 

 of hydrothecse or cell openings on their margins ; basal attachment 

 unknown. 



Inmost Island, Kin wow Bay, Lake Winnipeg, T. 0. "Weston, 1884 : 

 one well defined and nearly perfect specimen, though its minute structure 

 is not preserved. 



This specimen is so similar in general shape to some of the Devonian 

 and Carboniferous species of Plumalina that the writer has long been 

 under the impression that it could be referred to that genus. It is also 

 equally similar in general shape to the Buthograptus laxus of Hall, from 

 the Trenton shales of Wisconsin. According to S. A. Miller,* Ptilophy- 

 ton, Dawson, is a synonym of Plumalina, and the writer is informed by 

 Sir J. W. Dawson that he has recently ascertained that Buthograptus 

 laxus is exactly congeneric with., Ptilophy ton. In Hall's original descrip- 

 tion of Plumalinai the specimens described are said to have a ' well-pre- 

 served corneous structure,' and Whitfield has shown that the lateral 

 branches of Buthograptus laxus are articulated. Under a lens, the 

 specimen from Inmost Island shews no indication of corneous structure, 

 and its lateral ramifications are apparently continuous with the rhachis. 

 It would, therefore, seem to be the most prudent course to refer it 

 provisionally to the genus Chondrites. Whether viewed with or without 

 a lens, it has so many characters in common with C. cupressinus that 

 practically the only difierence between them is, that the one has long and 

 undivided pinnse or lateral ramifications, and the other short and much 

 divided ones." 



RECEPTACULITID^. 



Receptacdlites Oweni, Hall. 



Coscinopora sulcata, D. D. Owen (but not of 



Goldfuss) 1844. Rep. Geol. Expl. Iowa, Wiscons. and 



111., p. 40, pi. 7, fig. 5. 



Beceptaeulites Oweni, Hall 1861. Rep. Progr. Geol. Surv. Wiscons., p. 13. 



M II 1862. Rep. Progr. Geol. Surv. Wiscons., p. 



46, fig. 2, and p. 429. 

 „ Meek and Worthen. . .1868. Geol. Surv. 111., vol. III., p. 302, pi. 2, 

 fig. 3. 



Beceptaeulites Oweni Whitfield 1882. Geol. Wiscons., vol. IV., p. 239, pi. 



10, fig. 7. 



* North American Geology and Palaeontology, 1889, p. 136. 

 t Canadian Naturalist and Geologist, vol. III., p. 175. 



