175 



and by D. B. Dowling and L, M. Lambe in 1890; on Snake Island by 

 Messrs. Dowling and Lambe in 1890 ; and from Dog Head by Mr. 

 Lambe in 1890. In 1879 it was collected by Dr. R. Bell at the Lime- 

 stone Rapids of the Nelson River, in the district of Keewatin. 



Orthis tricenahia, Conrad. 



Orthis tricenaria, Conrad 1843. Proc. Ac. Nat. So. Philad. , vol. I. , p. 



333. 



Orthis disparilis, Conrad 1843. Ibidem, p. 333. 



Orthis testudinariaf?) Owen 1844. Geol. Expl. Iowa, Wisoons. and 111., 



pi. 15, fig. 11. 

 Orthis tricenaria, Hall 1847. Pal. N. York, vol. I., p. 121, pi. 32, 



figs. 8, a-d. 



Orthis disparilis, Hall 1847. Ibidem, p. 119, pi. 23, figs, 4, a-d. 



Billings 1859. Canad. Nat. and Geol., vol. IV., p. 



440, fig. 20. 

 Orthis tricenaria, Salter 1859. Canad. Org. Rem., Dec. I., p. 39, pi. 



9, figs. 1-4. 



HaD 1862. Geol. Wiscons. , vol. I. , p. 42, figs. 8-11. 



Orthis disparilis, Hall 1862. Ibidem, p. 435. 



Billings 1863. Geol. Canada, p. 130, figs. 60, a-b. 



Orthis tricenaria, Billings 1863. Ibidem, p. 167, figs. 151, a-b. 



Hall 1883. Second Ann. Rep. N. York St. Geolo- 

 gist, pi. 35, figs. 1-5. 



Waleott 1884. Mou. XT. S. Geol. Surv., vol. VIII., 



p. 74, pi. 11, fig. 4. 



Hall 1892. Pal. N. York, vol. VIII., pt. 1, pp. 



191, 193, 221, 228, pi. 5, figs. 9-12. 



Orthis disparilis, Hall 1892. Ibidem, pp. 191, 221, 228. 



Ort/ws irt'ccreaWa, Winohell and Sohuchert .. 1893. Lower Silur. Brach. Minn., p. 418, 



pi. 32, figs. 18-23. 



Lake Winnipeg, at Deer Island, from the basal beds of the limestone, 

 T. C. Weston, 1884, and J. B. Tyrrell, 1889; at Inmost or Birch Island, 

 and three miles west of Cat Head, D. B. Dowling and L. M. Lambe, 

 1890; and at Cat Head, D. B. Dowling, 1891. 



Orthis (DiifOETHis) pectinella (Emmons) Hall. 



Orthis pectinella, Emmons 1842. Geol. N. York, Rep. Second Distr. 



p. 394, fig. 2 (not defined). 

 Hall 1847. Pal. N. Y., vol. I., p. 123, pi. 32, figs. 



10, a-c. 

 var. semiovalis, Hall 1847. Ibidem, p. 124, pi. 32, figs. 11, and 



11, a-b. 

 Billings 1856. Canad. Nat. and Geol., vol. I., p. 205, 



fig. 5. 



Rogers 1858. Geol. Pennsylv. , vol. II. , p. 818, fig. 602. 



Billings 1863. Geol. Canada, p. 165, figs. 147, a-c. 



Orthis Oharlottm,^. H. Winchell 1880. Eighth Rep. Geol. and Nat. Hist. 



Surv., Minn., p. 67. 



