Brief Notices. 181 
Royal Astronomical Society of Canada in 1914 (reprinted Smithsonian 
Rep. for 1914 (1915), pp. 161-74) summarizes recent geodetic work 
on the form and constitution of the earth. The paper consists mainly 
of an account of the gradual measurement of the size of the earth, and 
finally discusses isostasy and allied problems. He accepts isostasy, 
and adopts the view that the earth is a cooling and shrinking body of 
which the crust accordingly is under the continual necessity of 
adapting itself to smaller space; and to this contraction he attributes 
earthquakes, and as probably none of them originate at a greater 
depth, he concludes the material at greater depths behaves as a fluid. 
He also holds the view that the earth as a whole is more rigid than 
steel. He summarizes the conclusions as to the rate of earthquake 
waves at different depths. 
4. Swattow-warer Depostrion 1n THE CAMBRIAN OF THE CANADIAN 
CorpituEra.—Under this title Mr. L. D. Burling publishes in the 
Ottowa Naturalist for November, 1915, evidence of shallow-water 
conditions during the deposition of Cambrian limestones in British 
Columbia and Alberta. Such evidences are mud-cracks, ripple-marks, 
and interformational conglomerate. Such proofs occur in the Middle 
Cambrian Mount Stephen formation, though not, of course, in the 
Burgess Shales; also at the base of the Upper Cambrian, in the 
Bosworth formation, where also are large casts of salt crystals. 
5. Tue Favunistic Inrivence oF LitrwoLocicaL CHARACTER.— 
Mr. L. D. Burling (Bull. Geol. Soc. America, vol. xxv, p. 421) has 
studied the relation of the genera and species of Brachiopoda to the 
sediments in which they are found, so far as concerns the Cambrian 
_.and Lower Ordovician rocks mainly in North America. Dividing 
sediments into shale, sandstone, and limestone, he finds that 41 per cent 
of the genera and sub-genera, 74 per cent of the species and varieties, 
appear to have been identified from but one type of sediment. About 
half of these, however, are represented by single species in single 
faunules or localities. Although the nature of the sea-floor does thus 
appear to exert some influence on the nature and number of the 
species (there are fewest in shale, most in limestone), still most species 
can accommodate themselves to changes in the character of the 
sediment, especially when the change is from more to less elastic. 
The study is of enough importance to be extended to other groups of 
animals. 
6. Grozocists’ Association or Lonpon.—Mr. George W. Young 
ended his presidency of this body on February 4, when he read his 
second annual address ‘‘On the Geological History of Flying”’. 
This year he dealt with Invertebrates, last year with Vertebrates. 
Mr. George Barrowe (late of H.M. Geological Survey) succeeded to 
the presidential chair. The usual list of proposed excursions is 
issued, many close to London and of exceptional interest. The 
‘long excursions’ have not yet been, fixed. 
7. Tue Zootoercat Recorp.—The annual volume for 1914 (vol. 11) 
has just appeared. Paleontologists may be reminded that all fossil 
forms are included, and that the literature of each group is published 
separately at a small cost. At the present moment the Zoological 
