166 



and acute, laminar concenLric ridges, not unlike those of L. Hurlburti, 

 N. H. Winchell, from the Galena limestone of Minnesota. It (the Cat 

 Head specimen) resembles figure 76, on plate 30 of the first volume of 

 the Palaeontology of New York, more than figure la on the same plate, 

 but is more narrowly rounded in front than the former and not quite so 

 obtuse at the beak. As compared with the representation of L. ohtusa 

 on page 161 of the " Geology of Canada," it is not quite so much elongated 

 in proportion to its breadth, and more obtuse at the beak. It is remark- 

 ably similar to specimens from the Utica slate near CoUingwood, in the 

 Museum of the Survey, which appear to have been identified with L. 

 obtusa by E. Billings. Mr. Schuchert, who has examined this specimen, 

 writes that "in form it is not L. Hurlburti" but that it "approaches it 

 in surface characters. It is more in harmony," he adds, "with L. ohtusa 

 or small L. Cohourgensis.'' 



DiNOBOLUS PARVUS, Whitfield. 



Sinobolus parvus, Whitfield 1882. Geol. Wisoons., vol. IV., p. 347, pi. 



27, figs. 8-10. 

 Dinobolus(?)parvus,W\nc'hei\&ndSc]iuchfTt.\.8Q3. Lower Silur. Brach. Minn., p. 356, 



figs. 27, A-D. 



West shore of Lake Winnipeg, north of the Saskatchewan and opposite 

 the north end of Selkirk Island, eight well preserved casts of the interior 

 of separate valves ; and Stonewall, Manitoba, a similar specimen but from 

 rocks that may be referable to the Hudson River group, all collected by 

 D. B. Dowling in 1891. Similar but not so well preserved specimens 

 have since been collected from loose pieces of rock on the west bank of 

 the Churchill River, at Port Churchill, Hudson's Bay, by J. B. Tyrrell 

 in 1894. 



Clitambonites diversa, Shaler. (Sp.) 



Orthisina diversa, Shaler 1865. Bull. Mus. Oomp. Zool., Cambridge 



No. 4, p. 67. 



Orthisina VerneuUi, Billings 1866. Geol. Surv. Canada, Cat. Silur. Foss> 



Anticosti, pp. 43 and 74. 



Hemipronites Americanus, Whitfield 1877. Ann. Rep. Geol. Surv. Wisconsin, p. 



72. 

 ■I M .1 . . . . 1882. Geol. Wisconsin, vol. IV., p. 243, pi. 



10, figs. 15-17. 



Streptorhynchus Americanus, Jliller 1889. N. Am. Geol. and Palseont., p. 378. 



Clitambonites Americanus, Hall 18ti2. Pal. N. York, vol. VIII-, p. 232, pL 



15a, figs. 1-8. 

 II ti Winchell and 



Schuchert 1893. Lower Silur. Brach. Minn. , p. 378 



pi. 30, figs. 11-17. 



Western shore of Lake Winnipeg, two miles south of Dog Head, D. B. 

 Dowling, 1891 : one imperfect but fairly characteristic specimen. 



