150 Scientific Intelligence. 



II. Geology and Mineralogy. 



1. Geological Survey of Canada. — Bulletin 33 of the Canadian 

 Geological Survey (109 pp., 12 pis., October, 1921 ) is made up 

 of the following papers : Faunal and Sediment Variation in the 

 Anticosti Sequence, by W. H. Twenhof el ■ New Species of Devo- 

 nian Crinoidea from Northern Canada, by Frank Springer ; The 

 Range of certain Lower Ordovician Faunas of the Ottawa Valley, 

 with Descriptions of some New Species, by Alice B. Wilson; The 

 Fossil Molluscan Faunas of the Marl Deposits of the Ottawa Dis- 

 trict, by E. J. Whittaker; and Two New North American 

 Cycadeoids, by Gr. R. Wieland. 



Professor Twenhofel sets forth in his paper very important 

 conclusions regarding the Anticosti Island Silurian and Ordo- 

 vician sediments and faunas. He says that "lateral gradation 

 of sediments and faunas may so develop that one type of sediment 

 with its fauna may overlap another — the conditions responsible 

 for one type of deposition migrating laterally with respect to the 

 other. The common interpretation would be 'overlap' of the 

 one by the other, a withdrawal of the sea, a land interval, and the 

 development of an unconformity." Twenhofel does not accept 

 this current interpretation of lateral changes, but states it to be 

 "the purpose of this article to describe examples of sediment and 

 faunal variation in the shallow Ordovician and Silurian seas in 

 which were deposited the sediments which now constitute the 

 rocks of the Anticosti sequence. ' ' 



Doctor Springer's paper describes and figures two new crinoids 

 belonging to the genus Melocrinus, from the Mackenzie basin. 



The paper by Miss Wilson materially increases our knowledge 

 of the geological range of the species comprising the Black 

 River and Trenton faunas in the Ottawa valley, and adds some 

 new forms to these faunas. The author shows the range of 

 species by means of a series of tables. These indicate at just what 

 point in the section each species makes its first appearance, and 

 just where it disappears from the section. This paper is a good 

 example of the sort of precise work in collecting and studying 

 fossil faunas which is very much needed. 



Mr. Whittaker 's contribution deals with a fresh-water fossil 

 fauna found in the marls of the Ottawa valley, which, in its time 

 relations, lies between the latest marine Pleistocene interval and 

 the living molluscan fauna. Students wishing to study the fresh- 

 water fossils of the Ottawa valley Pleistocene will find the plates 

 and keys of this paper most useful. The illustrations include an 

 aeroplane photograph showing the relation of the fossil marl 

 deposits to the present water-level at McKay Lake. So far as the 

 reviewer is aware, this is the first aeroplane photograph to be 

 used in illustrating a paleontological paper. 



