1 86 The American Geologist. September, 1905 
It is interesting to note that beautifully crystallized 
copper has been produced in trees resembling the aborescent 
native copper of the Soudan occurrence through electroly- 
sis.* This copper was formed at the lower corner of a full 
sized kathode operating under bad conditions in an insoluble 
anode tank, presumably with very high current density. 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
Structure of some Cephalopods, by R. Ruedemann. [Report of New 
York State Paleontologist 1903, Albany, 1905]. 
Notes on the apical end of the siphuncle in some Canadian Endo- 
ceratidae, &c. by J. F. White aves [American Geologist, Jan. 
1905). 
Ueber die eocambrische Cephalopodengattung Volborthella, Schmidt, 
von A. Karpinsky, (Verhandl. russ. miner. Gesell. Bd. xli, li, pp. 
31-42]. 
These papers with that of G. Holm 1895 on the formation of 
the endosiphon in the Endoceratidse help greatly to a proper under- 
standing of the initial stage of the shell in the early cephalopods. 
Especially is this the case with the first-named essay, based 
upon excellent material from the oldest Ordovician limestones of 
lake Champlain. The essay is valuable not only for what it tells 
us about the Beekmantown cephalopods, but also for the synopsis 
which it contains of the work of other observers in this field of re- 
search — Barrande, Dewitz, Whitfield, Dawson, Hyatt, Holm, Foord, 
Clarke and others. 
Ruedemann's work is based chiefly on the species Camerocera, 
brainerdi Whitfield, and fully describes the delicate chitinous and 
chitino-calcareous parts of the envelope in this species, which pre- 
ceded the formation of the calcareous shell. The assumption of 
the calcareous habit is plainly shown in the individual history of 
these shells, as it is in several of the Hyolilhidse of an earlier date. 
Dr. Ruedemann's work is abundantly illustrated with wood cuts in 
the text and a series of plates at its close. C. brainerdi began in a 
small cylindrical tube (endosiphotube, page 320) which became dif- 
ferentiated by the addition of an outward enclosing tube (endosi- 
phocoleon). The first named tube fades out or loses its chiten, 
J E. Haworth Native copper near Enid. Oklahoma, Bull. Geol. Soc. 
Am., vol. 12, 1901, pp. 2-4. 
*Lawrence Ad dicks. Electrolytic copper. Electro-chemical and 
metallurgical industries, vol. 3, 1905, p. 167, fig. 
