October 5, 1906.] 



SCIENCE. 



439 



catua, the largest genus, fourteen species are 

 recognized, and four additional subspecies are 

 casually mentioned, although the latter seem 

 worthy of a more prominent place. The sec- 

 ond subfamily contains only the single species 

 Calopsittacus novcehollandice. The two plates 

 depict nine species. 



Altogether, these first five parts of ' Genera 

 Avium ' are very creditable. The arrangement 

 is good, the exposition clear, and while not 

 so ample as some might wish, is yet probably 

 sufficient for the purpose of the publication. 

 The letter press is quite attractive in appear- 

 ance; and the plates, all of which are colored, 

 are excellent. This work will prove very use- 

 ful to all who wish to keep abreast of the 

 times, and will be well-nigh indispensable to 

 the working ornithologist. 



Harry C. Oberholser. 



SCIENTIFIC JOURNALS AND ARTICLES. 

 The American Journal of Science for Oc- 

 tober contains the following articles : 



A. L. Day and E. S. Shepherd : ' Lime-Silica 

 Series of Minerals,' with optical study by F. E. 

 Wright. 



0. C. Fakrington : " Analysis of ' Iron Shale ' 

 from Coon Mountain, Ariz." 



N. T. Bacon : ' Phenomena Observed in Crookes' 

 Tubes.' 



1. Bowman : ' Northward Extension of the At- 

 lantic Pi-eglacial Deposits.' 



H. C. Bradley : ' A Delicate Color Reaction for 

 Copper, and a Microchemical Test for Zinc' 



A. HiLEMAN : ' Elimination and Alkalimetric 

 Estimation of Silicon Fluoride in the Analysis of 

 Fluorides.' 



C. Barus : ' Note on the Actual Drop of Pres- 

 sure in the Fog Chamber.' 



C. Barus : ' New Method for Standardizing the 

 Coronas of Cloudy Condensation.' 



DISCUSSION AND CORRESPONDENCE. 



Stephens's California mammals. 

 In no part of the world is the effect of segre- 

 gation and isolation as a factor in species- 

 forming more evident than in California. No 

 other state of our union offers such diversities 

 of physical conditions, or such a variety of 

 barriers to the dispersion of animals. A 

 faunal map of California has been compared 



to a crazy quilt, because any such map must 

 recognize the limiting and modifying effects 

 of the different sets of environment connected 

 with the hills, valleys, mountains, lakes and 

 streams of this varied land. 



Because of the varying degrees of segrega- 

 tion produced by barriers of mountain and 

 climate, the non-migratory animals of Cali- 

 fornia are especially numerous in species, and 

 many of the recognized species are broken up 

 into numerous subspecies. Each form finds 

 its nearest ally farther on, across the range; 

 and, again, types once differentiated may in- 

 vade each other's territory, when conditions 

 enable individuals to cross the border. 



In a volume called ' California Mammals ' 

 (West Coast Publishing Company, San Di- 

 ego), Mr. Prank Stephens, of San Diego, has 

 brought together compact descriptions of all 

 the mammals thtis far recorded from Cali- 

 fornia. The descriptions are carefully writ- 

 ten, the accounts of habits are full and accu- 

 rate, the volume is well printed, and it can 

 not fail to be of great value to the students 

 of California beasts. Two hundred and sev- 

 enty-six species and subspecies are included in 

 the list. The volume contains also an excel- 

 lent essay on the 'Life Areas of California.' 

 Under the head of Homo sapiens americanus, 

 the most specialized of the indigenous mam- 

 mals of California, is given a map showing 

 the distribution of the twenty-one linguistic 

 stocks. 



David Starr Jordan. 



an ignored theory of the ice age. 



Looking over the recently issued work on 

 ' Geology ' by Professors Chamberlin and 

 Salisbury, I was surprised and disappointed 

 to learn that in this voluminous publication 

 of nearly two thousand pages, many of which 

 are devoted to considerations of causes lead- 

 ing up to the ice age, the name of Dr. Mars- 

 den Manson is not to be found. 



In a work like this, designed for the use 

 of students and general readers, views antag- 

 onistic to generally accepted dogmas and pet 

 theories, should, when endorsed by recognized 

 authority, find fair treatment. 



