676 SCIENTIFIC EECORD FOR 1884. 



Walcott, C. D. — Paleoutology of the Eureka District. (Monographs 

 of the United States Geological Surrey, vol. viii, i^p. i-xiii and 1-298, 

 pis. i-xxiv, and seven figures in the text. Washington, 1884.) 

 Gives an account of the very interesting paleozoic fauna of this dis- 

 trict. The first chapter contains a fair summary of the results. A com- 

 mingling of Upper Devonian and Lower Carboniferous fossils occurs. 

 The discussion of the development of Olenelliis HoiceUi is very interest- 

 ing. The succession in the fauual series from the Olenelius beds, 

 through a well-defined fauna of the character of the Potsdam group of 

 New York and the Mississippi Valley, to one containing a mixture of 

 Cambrian and Silurian types passing upward to a fauna comparable 

 to that of the Chazy and Calciferous groups, is shown. The transi- 

 tion is said to be very gradual, and such as would occur where there 

 had been no marked physical disturbance. Here is another instance of 

 the occurrence of passage beds between faunas before considered per- 

 fectly distinct, and it is very interesting to note this fact in our earliest 

 faunas, which is so common in our later ones. 



The author gives carefullj'^ prepared systematic lists of the fossils in 

 each formation and a paleozoic section of Nevada showing the vertical 

 range of the genera. Two new genera are described, Scldzambon, referred 

 to the SiphonotretidaB,from theL. Silurian Pogonii? group abndZaptychius, 

 an auricula-like shell, from the Carboniferous. The author describes one 

 hundred and seventy-three new species, of which thirty are from the 

 Cambrian: Acrothelef dicJiotoma, Scenella f conula, Kutorgina whitjieldi, 

 K. prospectensis, Orthis eiirel'ensis, Stenotheca elongata, Agnostus richmond- 

 ensis, A, seclusus, Olenelius iddingsi, Dicellocephalus nasutus, D. richmond- 

 ensis, D. ? angtistifrons, D. iolCj D. marica, D. f expansus, Ptychoparia f 

 prospecterisis, P. f linnarssoni, P. {Solenopleura f) breviceps, P.? {Soleno- 

 pleura ?) pernasutus, P. [Euloma) dissimiliSj P. {Euloma) Occidentalism P. 

 {Euloma)similis, P. {Euloma) affinis, P. (Euloma) laevieeps, P. {Petro- 

 cephalua) occidetia, Anomocare ? parvum, Agraulosf glohosus, Arethusina 

 americana, Ogygia ? spinosa, 0. f problematica. From the Pogonip 

 group of the Lower Silurian thirty-one species are described : Beceptacu- 

 lites mamillaris Newb. n. sp., li. elongata^ E. elUpticus, Obolella ambi- 

 gua, Sdiizambon typicalis, Orthis haniburgensis, 0. lonensis, Streptorhyn- 

 cus minor, Tellinomya f haniburgensis^ Modiolopsis occidens, M. pogoni- 

 pensis, Pleurotoniaria lonensis, Maclurea annulata, M. subannulata, M. 

 carinata, Metoptoma phUlipsi, 71/. f analoga, Coleoprion niinuta, Ryolithes 

 vanuxemi, Dicellocephalus Jinalis, D. inexpectans, Ptychoparia f annectans, 

 Bathyurus ? tuberculatus, B. ? congeneris, B. f simillimus, Oyphaspis ? 

 brevlmarginatus, Amphion nevadensis, Symphysurus ? goldfussi, Barran- 

 dia f McCoyi, Illaeiiuru,s eurelcensis, Asaphus caribounensis. From the De- 

 vonian sixtj'-one new species are described: Palaeomanon roemcri, Lin- 

 gula alba-]}inensis, Lingula lonenHis, L. ichitei, PhoUdops bellula, P. quad- 

 rangularis, Ikercidium devonicum, Chonetes macrostiiata, C. Jilistriata, 

 Productus {Productella) hallanus^ Productus hirsutiforme, Cyrtina david- 



