March, 1920] 



The Canadian Fikld- Naturalist 



55 



of marine dark shale. The Dunvegan is composed 

 cf sandstone and shale; the presence of some marine 

 shells demonstrates temporary marine conditions, but 

 the internal structure and nonmarine fossils indicate 

 predominantly subaerial deposition. The Smoky 

 River is made up chiefly of marine shale, with a 

 marine sandstone band (Bad Heart sandstone) at 

 or near the top of the Colorado part of the forma- 

 tion. 



Dunvegan Delta. The subaerial character of 

 the Dunvegan and its conformable relation to marine 

 beds above and below identify it as a delta built 

 out into the Colorado sea. The thinning of sand- 

 stone and its replacement by shale in an easterly 

 direction points to a western source of sediment and 

 the existence of high land there; it also indicates 

 that the delta was built out from the western shore. 

 It extended at least as far east as the Athabaska in 

 the Pelican-House River area. Southward it is not 

 thought to have reached far, but until the Colorado 

 group cf the Brazeau-Bighorn area is studied in 

 detail the southerly limit cannot be determined. 



Zonal Arrangement. Four fossil zones are 

 recognized in the local development of the Colorado 

 group. The St. John contains the first fauna with 

 Acanthoceras cornuium Whiteaves, large Inocer- 

 amus, etc. ; it may be quite early Coloradoan. A 

 part of the base of the St. John may represent a 

 marine equivalent of the Dakota. The second or 

 Dunvegan fauna contains, as guide fossils, Unio 

 dorvlingi McLearn, Corbula piriformis Meek, 

 Drach^dontes multdinigcra Meek, Or.lrea anomi- 

 oides Meek, and Barbatia nticronema (Meek.) Th" 

 third fauna is found in the lower part of the lower 

 shale member of the Smoky River and includes 

 Prionotropis hyaltl Stanton, Acanihoceras cf. coio 

 radoensis Henderson and Inoceranws labiatus 

 Schlotheim. The difference between the second 

 and third faunas can be explained by dissimilar en- 

 vironmental conditions; for the Dunvegan contains 

 freshwater, brackish water and marine sand bot- 

 tom forms, while the basal Smoky River represents 

 a shale facies with also ammonites. For the pur- 

 pose of correlation they may be treated as one fauna. 

 The fourth and highest zone, at the top of the lower 

 shale member and in the Bad Heart sandstone 

 member of the Smoky River, contains Scaphitcs 

 ventricosus M. & H., Daculites cf. asper Morton, 

 B. cf. anceps Lamarck, Inoceramus umbonatus M. 

 & H., Ox})toma nebrascana E. & S. and Pteria 

 Unguiformis E. & S. 



New Species. Of the three species described 

 below two are from the Dunvegan formation: 

 Tcllina dunveganensis, n.sp. 

 TcUina (Mocra) pcacerivcrensis, n.sp. 



One is from the Bad Heart sandstone: — 

 Cervillia stanloni, n.sp. 



Phylum MOLLUSCA. 



Class PELECYPODA Goldfuss. 



Order PRIONDESMACEA Dall. 



Family PERNIDAE Zittel. 



Genus CERVILLIA Defrance. 



Cervillia stanloni, n. sp. FiG. I . 



This species is smaller and less oblique in out- 

 line than Certyillia recta var. borealis Whiteaves and 

 C. subtortuosa Meek and Hayden. The size is 

 about as in C. recta Meek and Hayden, but it is 

 not nearly so oblique in outline and is wider pio- 

 portionately on the hinge line. 



The species name is given in honour of Doctor 

 T. W. Stanton of the U. S. Geological Survey. 



Height 40 m.m. ; length 42 m.m. ; length of hinge; 

 line 35 m. m. 



Horizon and Locality. Rare in the Bad Heart 

 sandstone member of the Smoky River formation. 

 Smoky river. Alberta. 



Collection. Holotype Cat. No. 5669 in the Vic- 

 toria Memorial Museum, Ottawa. 



Order TELEODESMACEA Dall. 



Family TELLINIDAE Deshayes. 

 Genus Tellina Linne. 

 Tellina dunveganensis, n. sp. FiCS. 2, 4. 



A trigonal, moderately depressed, shell with sub- 

 central beaks and somewhat angular post-umbonal 

 slope. External ligament very short; pallial sinus 

 rounded and shallow; lateral teeth well developed 

 and the anterior one approximate; two stout cardin- 

 al teeth in the left valve. 



Height 18 m. m. ; length 25 m. m. 



Horizon and Locality. Rather rare in the Dun- 

 vegan formation. Peace and Smoky rivers, Alberta. 



Collection. Holotype Cat. No. 5671 in the Vic- 

 toria Memorial Museum, Ottawa. 

 Tellina (Mocra) pcaceriverensis, n. sp. FiGS. 5, 6. 



Only molds of the left value are preserved. The 

 outline resembles that of Donax cuneata Stanton, 

 but this species is not so abruptly deflected on the 

 postumbonal slope, is not curved upward at the 

 anterior end, and the beak is not so prominent or 

 terminal. Donax? oblonga Stanton is a larger 

 shell with more prominent beak and is more angular 

 and abruptly deflected on the post-umbonal slope. 



The form of this species suggests the genus 

 Donax; but the dentition is like Tellina and the 

 outline is closest to subgenus Moera. The left 

 value has two cardinal teeth, the posterior much 

 smaller than the anterior. The lateral teeth are too 

 well developed for Donax; the anterior lateral is 

 approximate as in Tellina. Ligament not known. 



