38 CALIFORNIA ACADEMY OF SCIENCES. 



The Hercyn-frage and the Helderberge Lime- 

 stone in North America. 



lu American Geologist, vol. 7, 1891, p. 109. 



Notes on the genus Acidaspis. 



Author's ed., 1892. Commimicated to the N. Y. State Geologist, Dec, 

 1890. In 44th Rep. N. Y. State Mi;s., 1892. 

 The author proposes the following scheme of classification: 

 Genus Ceraiocephala, Warder, 1838. 



1. Species having the occipital ring: (a) Smooth, or ^Yi*'ll ^ central 

 tubercle. do7itopleur a 'Emmrich, tjiie O.ovata 'Emm., (h) With a single 

 large straight median spine. Acidaspis Murchison, type A. brighti Murch. 

 sjn.. Ac antholoma Gonx&A. (c) With two straight divergent spines. Cer- 

 a<oce/-iA«7a Wardei-, sensu stricto. Type C.goniata Warder. (cl) With 

 two spirally recurved spines of great size. Dicrcmurus Conrad. Type 

 D. hamatus (Conrad) Hall. 



2. Species with confluent glabellar lobes, oblique thoracic pleurse and 

 spineless pygidium. (e) Selenopeltis Corda. Type S. biichi Barr. syn. 

 Pohjeres Eouault. ff) Ancyrop)yge n. subgn. Type Acidaspis romingeri 

 Hall. Ceraiocephala goniata Ward. Acidaspis verneuilli Barr. Trape- 

 locera hoernesi Cord. Dicraniirus hamatus Conrad. Acidaspis monstrosa 

 Barr., A. brighti Mxirch., A. monstrosa Barr., A. romingeri Hall. Odon- 

 tojileura ovata Emm. Selenopeltis stephnni Cord. 



Note on Coronura a.Hpectans Conrad. The 



Asaphtis diurus Green. 



Author's ed., 1892. Communicated to the N. Y. State Geologist, Dec, 

 1890. In 44th Rep. N. Y. State Mus., 1892, p. 105. 

 Coronura diurus Green, pi. 4. 



Observations on the Teratasjns grandis Hall. 



The largest known trilobite. 



Author's ed., 1892. Commiinicated to the N. Y. State Geologist, Dec.^ 

 1890. In 44th Eep. N. Y. State Mus., 1892, p. 111. 

 Terataspis grandis Hall, plate. 



Clarke (W. B.) On the occurrence of Trilobites in 

 New South Wales. 



In Quart. Jour. Geol. Soc. London, vol. 4, 1848, p. 63 (not descrii^tive). 



Claypole (E. W.) Note on a large Crustacean from 

 the Catskill group of Pennsylvania. 



In Proc. Am. Philos. Soc, Phila., vol. 21, 1883, p. 236, plate. 

 Dolichoceph(da n. g., D. lacoana n. sp. 



