whcteavee] fossils OF HAMILTON FORMATION OP ONTARIO. 391 



Tropidoleptus carimtus, Nettelroth. 1889. Kentucky Fossil Sheila, Mem. Kent. Geol. 

 Surv., p. 146, pi. 17, figs. 14 k 1.5. 

 " " A. "Ulrich. 1892. Neiies Jahrb. fur Min., Geol., and Pateont, 



Beilageband, VIII., p. 73, pi. 4, figs. 32-34. 



Hall and Clarke. 1893. Pal. N. York, vol. VIII., pt. 2, p. 304, 

 figs. 227 and 228 ; and pi. 82, figs. 2U-36. 



A few specimens of this widely distributed brachiopod have recently 

 been collected at Thedford. They are rather similar in shape and 

 sculpture to Stropheodonto, plicata, which occurs at the same locality and 

 geological horizon, but the latter shell has a long and transversely stri- 

 ated cardinal area and its test is impunctate. 



Atrypa spinosa, Hall. 



Atrtjpa spinosa, Hall. 1843. Geol. N. York, Rep. Fourth Distr., p. 200, figs. 1 and 2. 



Atrypa dumosa, Hall. 1843. Ibid., p. 271, fig. 1. 



Atrypa aspera, Hall. 1857. Tenth Rep. N. Y. St. Cab. Nat. Hist., p, 168. 



.. I. Rogers. 1858. Geol. Pennsylv., vol. II., pt. 2, p. 828, figs. 671. 



Atrypa spinosa, veX aspera. Hall. 1867. Pal. N. York, vol. IV., p. 322, pi. 53 A, figs. 



1-14, 18, 24 and 25. 

 Atrypa aspera. Meek. 1868. Trans. Chicago Ac. So., vol. I., p. 96, pi. 13, fig. 12. 

 Atrypa spinosa, Nicholson. 1874. Rep. Pal. Prov. Ontario, p. 80. 



Whitfield. 1882. Geol. Wiscons., vol. IV., p. 333, pi. 26, figs. 7 and 8. 

 Atrypa aspera, Nettelroth. 1889. Kentucky Fossil Shells, Mem. Kent. Geo). Surv., 



p. 88, pi. 14, figs. 1-11. 

 Atrypa reticularis, var. aspera, Whiteaves. 1891. This vol., pt. 3, p. 229 ; and (1892) 



pt. 4, p. 289. 

 Atrypa spinosa, Hall and Clarke. 1895. Pal. N. York, vol. VIII., pt. 2, pi. 55, figs. 

 21 and 22. 

 rt u Schuchert. 1897. Synops. Amer. Foss. Brachiop., p. 156. 



A shell which Mr. Billings calls a coarse-ribbed variety of Atrypa 

 reticularis is figured as one of the characteristic fossils of the Hamilton 

 formation of Ontario, on page 384 of the "Geology of Canada" (1863), 

 and a single specimen, collected at Thedford by Mr. E. Macintosh in 

 1895, has been identified with the A. spinosa of Hall by Mr. Schuchert. 

 In two previous parts of this volume A. spinosa was regarded as syno- 

 nymous with the Atrypa reticularis, var. aspera of European palseontolo- 

 gists, but as A. spinosa is still regarded as a valid species, the writer has 

 thought it better to retain that name for the present and to give only 

 American references. Thus, the Rev. G. F. Whidborne, in the third 

 part of the second volume of his Monograph of the Devonian Fauna of 

 the South of England, published by the Palseontographical Society in 

 1893, makes the following remark in reference to Atrypa aspera (Schlo- 

 theim). " Atrypa spinosa, Hall, A. hystrix. Hall, and A. aspera, v. occi- 

 dentalis, Hall, do not seem to me to be identical with this species, but 

 closely allied." Professors Hal) and Clarke, also, in 1895, in their 



