578 Scientific Intelligence. 



II. Geology. 



1. Neio York Potsdam- Iloyt Fauna and Group Terms for 

 the Lower and Upper Cambrian Series of Formations ; by 

 Charles D. Walcott. Smithsonian Misc. Coll., Vol. 57, Nos. 

 9 and 10, pp. 251-307, pis. 37-49, 1912.— The first paper is in the 

 main a description of the Potsdam and Hoyt faunules, the former 

 having 19 species (4 new) and the latter 10 (1 new). Lingulepis 

 acuminata is the only species common to both assemblages. A 

 new genus of gastropod, Matherella, is described. The striking 

 new illustrations are as follows : (1) Climactichnites, a track that 

 may have been made by a mollusk (Woodward) but which Wal- 

 cott thinks is the trail of a large annelid ;. (2) tracks of Protich- 

 nites that " were made by trilobites of the genus Dicellocephalus''' 

 (278) ; and (3) the four fine figures of the Middle Cambrian tri- 

 lobite Neolenus serratus, showing remarkably long and stout walk- 

 ing legs with three terminal spines that are also thought to have 

 been present in Dicellocephalus (Protichnites track). 



Walcott still regards the Potsdam-Hoyt formations as belong- 

 ing " to the upper limit of the Cambrian" (p. 255) and dissents from 

 Ulrich's view that they belong higher in the geologic scale. 

 They are equivalent, he states, " with the fauna of one of the 

 upper horizons of the 'St. Croix sandstone ' and thus included in 

 the Upper Cambrian" (p. 255). 



Due to the principle of priority of definition and the limitation of 

 a stratigraphic term to one meaning, Walcott in No. 10 substitutes 

 Waucoban (from Waucoba, California) for the series (or Lower 

 Cambrian) term Georgia. The latter is, therefore, to be retained 

 as originally proposed for the slates of Georgia, Vermont. For 

 similar reasons Walcott's series term Saratogan cannot be 

 retained as it is based upon the Saratoga formation of New York, 

 and further the name is preoccupied by Branner for a Cretaceous 

 deposit of Arkansas. Walcott now proposes that we use St. 

 Croixan, based upon N H. Winchell's " St. Croix beds" named 

 by him in 1873. In 1902 (p. 636) Ulrich and Schuchert called 

 this late Middle and Upper Cambrian sea invasion the " St. Croix 

 invasion "and Ulrich in 1911 also used as a stratigraphic term 

 " St. Croixan," the equivalent for his Upper Cambrian. Under 

 these circumstances the term St. Croix has now three meanings 

 and according to modern geologic usage can be retained only in 

 one sense, namely, that of the first user. As subsequent workers 

 have given names to the different members of the St. Croix beds 

 and as Winchell used the term for all the Cambrian deposits of 

 the upper Mississippi region, his term could by general consent 

 be used in the sense proposed by Ulrich and Walcott, but accord- 

 ing to strict usage and the rules employed by the U S. Geolog- 

 ical Survey, it seems to the reviewer that it cannot now be used 

 in this wider and double sense. The proposer of a new substitute 

 will have to bear in mind the systemic term " Ozarkian " of 

 Ulrich, and the complications are, therefore, many. c. s. 



