196 EDITORIAL 



collecting, and places within reach of students and teachers of 

 petrology material of the highest value, making it possible to 

 follow intelligently the descriptions by the investigators already 

 named, of the rocks in the Keweenaw, Penokee, and Marquette 

 districts. The collector had the advice and counsel of Professor 

 Van Hise, who vouches for the care with which the work has 

 been carried on. Not the least valuable part of the undertaking 

 is the furnishing of a catalogue in which specific references to 

 the monographs of the region are given in connection with each 

 specimen. The hand specimens are accompanied by chips from 

 which thin sections may be prepared. The enterprise is to be 

 heartily commended, and it is hoped that a sufficient number of 

 petrologists will avail themselves of the opportunity of securing 

 the collections to compensate Mr. Rohn for the time and money 

 expended upon them. ^ ^ J- f • I- 



Emm. de Margerie and his colaborers of the bigliograph- 

 ical committee of the international congresses of Washington 

 and Zurich merit the warmest commendation of all working 

 geologists for their disinterested labors in preparing and issu- 

 ing a voluminous report under the title Catalogue des Bibliog- 

 raphies Geologiques. This is a book of 733 pages, and represents 

 a very protracted and laborious search for bibliographical lists 

 through a scattered and voluminous literature whose very 

 unequal nature must have taxed the patience, skill and discre- 

 tion of the committee to the utmost. The catalogue contains 

 nearly 4000 references to bibliographies and works containing 

 bibliographic references of some note, and thus it constitutes an 

 invaluable key to geological literature. Provision has been made 

 whereby those who were not members of the international con- 

 gresses under whose auspices the work was prepared and pub- 

 lished may secure it, together with the Compte Rendu of the 

 Washington congress. The two volumes wilLbe sent to individ- 

 uals or libraries who will transmit $5 to the American member 

 of the committee, G. K. Gilbert, of the United States Geological 

 Survey, Washington, D. C. We would particularly urge upon 

 libraries the purchase of this catalogue. T. C. C. 



