170 CALIFORNIA ACADEMY OF SCIENCES. 



(leferred by Dr. D. D. Owen, in lS.i2, to Ilhtnus ovalis); pi. 17, fig. 9, 

 ThalcopH ? ; pi. 18, fig. 2, Asaphu.'<; fig. 10 {Amphus platyce/ihahi.s Stokes); 

 fig. 11, Ce.raurus. 



Keport of a geological reconnoissance of the 



Chippewa Land District of Wisconsin and incidentally 

 of a portion of the Kickapoo country, and a part of Iowa 

 and of the Minnesota Territory, etc. Washington, 1848. 



This reiDorl coutains figures of the following fossils, which were after- 

 wards described bj^ Dr. Owen iinder the names of Dikelocephabis minne- 

 soiensis, pi. 7, figs. 2, 3; LonrhorejihabiA hamulus, pi. 7, fig. 5; Dikeloceph- 

 alus ? ioivensis, pi. 7, fig. 1. 



Report of a geological survey of Wisconsin, 



Iowa and Minnesota, and incidentally a portion of Ne- 

 braska Territory. Philadelphia, 1852, 638 pp., 27 pis.,. 

 16 sections and maps. 



Dr. Owen described four new genera of trilobites iinder the names of 

 JJikelocephnlus, Lonchocephalus, Crepicephcdus and Menocephalus. The 

 second genus is now classed as a synonym to Avomocare, with Anomocare 

 chippewaensis and A. hamulus described in the report. There is a third 

 species mentioned by Owen on p. 624, and also pi. la, fig. 15. Pygidinm 

 of Lonchocephalus ?, with long, slender, divergent caudal spines; also a 

 similar pygidinm, figured pi. la, fig. 13, as Dikelocephalus ? iowensis. 

 Walcott, Bull. U. S. Geol. Sur., No. 10, p. 36, places the latter species 

 under a subgenus to Ptychoparia, using Dr. Owen's Crepicephalus for it^ 

 on account of the peculiar pygidium, overlooking, howevier, the fact that 

 Owen has referred a similar pygidium directly to his genus Lonchoceph- 

 alus on p. 624 of his report. Under the law of loriority the genus Ptycho- 

 paria replaces Crepicephalus, and the latter name should be cancelled 

 171 toto, and not be retained in a modified sense. Lonchocephalus forms an 

 exception to this rule, if we divide the genus into two sections, retaining 

 Anomocare for the two species described by Owen, and Lonchocephalus, in 

 a restricted sense, for "the pygidium with long, slender, divergent caudal 

 spines," including the Dikelocephalus ? ioicensis Owen. 



The author also describes and illustrates the following species: 1, Dikel- 

 ocephalus minnesolensis n. sp. 2, D. minisccensis n. sjj. 3, D. pjepinensis 

 n. sp. 4, D.? ioicensis n. sp. o, D. i/ranulosus n. sp. 6, Lonchocephalus 

 chippeivaensis n. sp. 7, L. hamulus n. sp. 8, L. sp.? 9, Menocephalus 

 miiinesotensis n . sy) . 10, Crepticephalus minisccensis n. s^). 11, (J. wisconensis 

 n. sp. 



The following species are mentioned or illustrated: 12, Phillipsia sp. 

 undet. 13, P. ijranulifera > 14, P. pustulata. 15, Calymene senaria 

 Conrad, pi. 2a, fig. 12. 16, C. crnssimarginata, pi. 3a, fig. 6. 17, C n. sp., 



