Reviews — Wakott's Lower Cambrian or Olenelhis Fauna. 35 



^States, and on the eastern slopes in British Columbia. There the 

 ^reat thickness of conformable pve-Olenelliis zone strata presents a 

 most tempting field for the student-collector" (p. 595). 



As the author remarks, a considerable number of the genera and 

 species included in this Monograph have already been described 

 at length and figured in Bulletin No. 30 of the U. S. Geological 

 Survey (1886). Beginning with the sponges, which are bj'' no 

 means nuuierous, we find Salter's genus Protospongia represented by 

 detached spicules of the usual type, and portions of the anchoring 

 rope of another hexaotinellid sponge, similar to those usually referred 

 to Hyalostelia, Zittel, have been placed by the author in a distinct 

 genus, Leptomitus. It may be remarked that since the discovery, 

 by Sir J. W. Dawson, that certain species of Protospongia possessed 

 anchoring spicules, it is nat impro-bable that forms like this Lepto- 

 mitus may be found to belong to the former genus. The above 

 are the only definite sponges known from the Lower Cambrian, for 

 the specimens of Girvanella, even if they really belong to this genus, 

 have no claim to be considered as sponges, and they are now believed 

 to be calcareous algae. The position of another new form, Tracliyum 

 vetustum, appears to be very uncertain, the description leads one 

 rather to consider it a member of the next group of the Archseocya- 

 thinae.. This group is very fully represented in the Lower Cam- 

 brian of Nevada, New York and Labrador, and very good figures 

 are given to illustrate the structure of the different genera. The 

 author follows Hinde in placing these peculiar forms in the Actinozoa. 

 Very considerable interest attaches to them, since they appear to be 

 characteristic of the Lower Cambrian, not only in America, but 

 in Spain and Sardinia, and, as lately shown by R. Etheridge, jun., in 

 South Australia as well. 



Of the fine series of plates which illustrate the fauna of the 

 Olenelhis or Lower Cambrian Zone, plate xlix. is devoted to Lepto- 

 mitus Zittelli and Protospongia sp. ? two forms of Sponges ; plates 

 l.-lv. to a series of figures of different forms of the Archgeocyathinje, 

 in some of which structure and ornament are preserved. Plates 

 Ivi.-lix. to forms referred to the Hydrozoa. Plates Ix.-lxvi. to 

 Echinodermata, Annelida, and Crustacea, being tracks, trails, and 

 Annelide- and Crustacean-burrows of all kinds. Plates Ixvii.-lxxii. 

 are devoted to a series of Brachiopods — Lingulella, Acrotreta, Linnars- 

 sonia, Kutorgina, Lphidea, Acrothele, MicTcwitzia, Obolella, Camarella, 

 Orthis, and Orthisina, mostly well-preserved and well-defined species. 

 Then follow plates Ixxiii.-lxxiv., devoted to Lamellibranchs and 

 Gasteropods, in which Patella-shaped forms predominate. Plates 

 Ixxv.-lxxix. are devoted to Pteropods (under which are included 

 Salterella, Hyolithes, Helenia, Coleoloides, Volborthella, and Plafy- 

 solenites. The remaining plates, pis. Ixxx.-xcviii., are devoted to 

 the Crustacea, and principally to the Trilobites. A few Ostracods 

 and Leperditia, with Agnostiis and Microdiscas, occupy plates Ixxx. 

 and Ixxxi., followed in the remaining plates by a grand series of 

 Olenelli which would have rejoiced the heart of J. W. Salter, could 

 he but have lived to see and gloat over them. Trilobites — many of 



