Prof. T. Rtipert Jones — Canadian Ostracoda. 25 



depression, and behind it with two roughly triangular sulci, close 

 together, and reaching to the hinge-line. 



Candona eupledella, Eobertson, Brady, and Norman, has a nearly 

 oblong outline, but no sulcus, and is too thick to be comparable with 

 our Fig. 5. On the other hand, some examples of the freshwater 

 Limnicythere and Ilyocypris have variable transverse depressions and 

 suboblong valves; and of these Ilyocypris gibba^ (Cypris, Eamdohr) 

 has the nearest resemblance to Fig. 5. Bythocythere constricta, G. 0. 

 Sars, is one of the few analogues among the marine Cytheridce. 



Four specimens in fragments of the unattached block of Saint- 

 Mary-Eiver Beds, above mentioned. 



Nos. 3, 4, and 5 indicate brackish and freshwater habitats. 



III. Six small specimens of light- and dark-brown limestone, four 

 from the nodular, and two from the concretionary layer, with small 

 Taludince, from the North Branch of the Milk Eiver, which, in the 

 "Eeport of Progress, Geol. Survey of Canada," 1885, at pages 13 C 

 and 36 C, is described as rising in the foot-hills south of the 49th 

 parallel; crossing that line near the 113th meridian, it pursues a 

 north-easterly tortuous course. Its North Branch was termed the 

 " Second Branch " in the " Eeport on the Geology and Eesources of 

 the 49th Parallel," p. 131 ; and its geology was described in the 

 " Eeport of Progress," 1885, pages 36 C and 37 C, thus :— 



The strata in the river-valley here belong to the Saint-Mary- 

 Eiver siabdivision, showing about fifty feet of soft sandstones and 

 shales, with harder bands, one of which is a nodular ferruginous 

 limestone, one foot thick, with Bulinus, Limrma, Physa, and Splim'ium. 

 A loose block of similar rock was found about fourteen miles south- 

 eastward, at the crossing of the 49th parallel and the South Branch 

 of the Milk Eiver (termed "First Branch" in the Eeport of 1875) ; 

 and the stratum to which it belonged is the same as that occurring 

 in the upper part of the Saint-Mary-Eiver Series (page 58 0). 

 This series constitutes the lowest portion of the Laramie formation ; 

 and consists of sandstones, shales, and shaly clays in frequent 

 alternations, and generally well bedded. Freshwater except near 

 base: 2800 feet. See also pages 114 C, 97 C, 57 C, and 37 C, for 

 other details. With the Willow-Creek Beds, next in upward 

 succession, and the Porcupine-Hill Beds at the top, these three 

 subdivisions constitute the Laramie Group in the District of the 

 North-west Territory. But some of the Laramie is regarded as 

 transitional from the Cretaceous to the Tertiary ; the plant-remains 

 being Tertiary, and the other fossils Cretaceous. 



Cythere, Muller, 1785. 



6. Cttheke, sp. indeterminate. PL II. Figs. 6a, h, c. 



Length I'O ? height '6 mm. 



Two contiguous valves, showing insides ; both imperfect, but one 



1 For S-^Tionyms, see Supplera. Monogr. Tert. Entom. Pal. Soc. 1889, p. 9 ; and 

 Trans. E,. Dublin Soc. ser. 4, vol. ii. 1889, p. 107. 



