WHITEAVES.] DEVONIAN FOSSILS, MACKENZIE RIVER BASIN. 219 



The specimens from the Clearwater and other Canadian localities 

 which have been referred to 0. lowensis appear to the writer to be 

 practically indistinguishable fi-om 0. striatula, even as a local variety. 

 At any rate they seem to correspond much better with Schnur's figures 

 of specimens of 0. striatula from the Eifel, and with Davidson's Illus- 

 trations of British examples of the same species, than they do with 

 Hall's figures of the types of 0. lowensis and its variety furnarius. 



It is probably this species that was collected by Sir John Richardson 

 m 1S25 on the Shive Eiver, forly miles below Lake Athabasca and 

 referred to, on the authority of Mr. J. DeCarle Sowerby,* as a tere- 

 hratula which resembles the T. resupinata. Judging by what is known 

 of the geology of this region the shell last named could scarcely be 

 the Liassic fossil now known as WaUheimia resupinata but by no means 

 improbably the Orthis resupinata (Martin, sp.) of the Carboniferous, the 

 Terebratula resupinata of Plate 32.5 of the " Mineral Conchology," 

 which is regarded by many paleontologists as a variety of 0. striatula. 



Strophodonta demissa (Conrad). 



Strophomerta demissa, Conrad. 1842. .Touni. Ac. Xat. Sc. I'hil, vol. VIII, pt. 2, 



p. '?38, pi. xiv, fig. 14. 

 Strophomena (Stropliodoata) demissa, Hall. 1857. Tenth Reg. Kep. N. Y. St. Cab. 



Nat. Hist., p. 137. 

 Strophodonta demissa, Hall. 1858. Geol. Iowa, vol. I., pt. 2, p. 4!I5, pi. iii, fig. 5. 

 Strophomena demissa, Billings. 1861. Canad. .lourn., X. S., vol. VI, p. 341, fig.s. 



116-118. 

 Strophomena demissa, Billings. 1863. Geol. Canada, p. 367, figs. 377 a-d. 

 Strophodonta demissa, Hall. 1867. Pal. N. Y., vol. IV, pp. SI, 101 and 114, pis. 



xi, xii, xvii and xix. 

 Strophomena (Strophodonta) demissa, ileetv. 1868. Trans. Chicago Ac. Sc, vol. I, 



p. 87, pi. xiii, figs. 6 a-c. 

 Strophodonta demissa, Nicholson. 1873. Kep. Palicorit. Prov. Ontario, |i. 65. 



Whitfield. 1883. Geol. Wisconsin, vol. IV, p. 327, pi. xxv, 



fig. 18. 

 " Walcott. 1884. Paheont. Eurel<;a distr. Nevada, p. 118, pi. 



ii, figs- 9 a-b. 



Peace River, at Rapid Bouille, Professor Macoun, 1S75 : one perfect 

 specimen. Hay Eiver, fortj' miles above its mouth, R. G. McConnell, 

 L887: eleven specimens. Peace River, at Vermilion Falls, R. G. Mc- 

 Connell, 1889 : three specimens. Athabasca River, thi-ee miles below 

 the Calumet, (eight specimens) and thirty miles below the Red River 

 (six specimens), R. G. McConnell, 1890. 



* On page 57 of Aiipendix No. 1 to Sir John Franlilin's " Njirnitive of a Second Expedition 

 to the shores of the Polar Sea. 



