Phillips — Vanadium in Sedimentary Rocks. ±75 



solution would precipate vanadium as the sulphide, to be 

 covered up and preserved as a small vanadium content, 

 in this case, of a future limestone. 



Vanadium also forms double salts with copper and 

 calcium, as in case of the minerals volborthite (CuCa) 3 - 

 (OH) 3 V0 4 6H 2 and calciovolborthite (CuCa) 2 (OHJ- 

 V0 4 . It would seem that both of these minerals would be 

 possible under the conditions described, as the ash of this 

 holothurian also contains 0-0045 per cent of copper, and 

 it has been shown that many forms contain both copper 

 and zinc which also enters into the composition of vana- 

 dium minerals. 



With small amounts of vanadium disseminated in cer- 

 tain sedimentary rocks and limestones, it is not difficult 

 to explain its secondary concentration in the fissures, 

 faults or joints of these same or nearby rocks. 



Geological Department, 



Princeton University, May 18th, 1918. 



SCIENTIFIC INTELLIGENCE. 



I. Geology and Mineralogy. 



1. Fossil Plants: A text-book for students of Botany and 

 Geology ; by A. C. Seward. Vol. Ill, small 8vo, pp. xviii, 656, 

 with 253 text-figures, and frontispiece portrait of Zeiller. Cam- 

 bridge, 1917 (The University Press). — A notice of the first vol- 

 ume of this work (1898) was given by G. L. Goodale in this 

 Journal in June, 1898 (5, 472) ; and of the second by the writer 

 in November, 1910 (30, 356). Continuing from the Pterido- 

 sperms not directly recognized as seed-bearing, with which vol. 

 II closes, the main topics of the present volume are: Pterido- 

 spermeee, Cycadofilicales, Cordaitales, Cycadophyta. The intro- 

 ductory pages are occupied by an interesting account of the 

 existing cycads ; the critical discussion of mesarch bundles 

 (p. 32) being noteworthy. The bibliography appended is not 

 impeccable; both the monographs of Fontaine on the Mesozoic 

 Floras are unnoted, and this omission of fine American material 

 represents a serious gap in Professor Seward's general dis- 

 cussion. 



There are many special features in the assemblage of indis- 

 pensable data for both reader and student. In some cases there 

 is a tendency to arbitrary treatment, always most difficult to 

 avoid during condensation of extensive work in the light of new 

 facts. Generally the points are well taken. Lyginodendron 

 becomes Lyginopteris, and Bennettites is relegated to the syn- 



