WHITEAVES.] DEVONIAN FOSSILS, MACKENZIE RIVER BASIN. 227 



Cyrtina Hamiltonensis, Ha,]\. 1867. Pal. N. Y., vol. IV, p- 268, pi. xxvii, figs. 1-4, 



and pi. xliv, figs. 26-33, 38-52. 

 Cyriina HamiUonensis, Meek. 1868. Trans. Chicago Ac. Sc, vol. I, p. 99, pi. xiv, 



figs. 5, 7 and 10. 

 Cyrtina HamiUonensis, Nicholson. 1874. Rep. Pal. Prov. Ontario, p. 83. 

 " " Walcott. 1884. Pal. Eureka distr. Nevada, p. 147. 



Mackenzie Eiver, at the " Eamparts'' (two specimens), and ten 

 miles below the "Eamparts" (one specimen), E. G. McConnell, 1888. 

 The species had p)i'eviously been collected at the "Eamparts," in 1859, 

 by Major Ivennicott, and near Port Good Hope, five miles below the 

 "Eamparts,"' in 1884, by Mons. I'Abbe Petitot. 



Athabasca Eiver, three miles below ihe Calumet, E. G. McConnell, 

 1890 : a few perfect and well preserved spiecimens. 



Ctrtina Billingsi, Meek. 



Cyriina Billiiuju, Meek. 1868. Trans. Chicago Ac. Sc, vol. I, p. 97, pi. xiv, 

 fig. 6. 



Athabasca Eiver, thirty miles below Eed Eiver, E. G. McConnell, 

 1890 : one tine and perfect large specimen, and a similar but much 

 smaller one. 



Athtbis Angelica, var. occidentalis. 



Plate 32, figs. 3, 3a, b. 



Athyris Angelica, Hall. 1861. Fourteenth Rep. Reg. N. Y. St- Cab. Nat. Hist., 



p. 99. 

 Athyris Angelica, Hall. 1867. Pal. N. Y., vol. IV, p. 292, pi. xlvii, figs. 9-20. 



Shell like the type of .4. Angelica, but much smaller and more dis- 

 tinctly biplicated. Ventral valve with two widely divergent rounded 

 and prominent plications, which extend to the beak, with a shallow 

 sinus between them. Dorsal valve with a broad flattened mesial fold 

 and a narrow divergent one on each side. The surface markings seem 

 to consist of concentric striations only, no trace of any radiating lines 

 being visible even under a lens. In average examples the greatest 

 breadth is about half an inch and the maximum length a little less. 

 The largest specimen collected, a detached ventral valve, is 15.5 mm. 

 (or about five eighths of an inch) in its gi-eatest breadth and 13.5 mm. 



