The Journal of Geology 



Edited By 



thomas c. chamberlin and rollin d. salisbury 



With the Active Collaboration of 



SAMUEL W. WILLISTON ALBERT JOHANNSEN 



Vertebrate Paleontology Petrology 



STUART WELLER ROLLIN T. CHAMBERLIN 



Invertebrate Paleontology Dynamic Geology 



ALBERT D. BROKAW 



Economic Geology 



The Journal of Geology is published by the University of Chicago at the University Press semi- 

 quarterly, on or about the following dates: February I, March 15, May 1, June 15, August 1, September 15, 

 November 1, December 15. 1|The subscription price is $4.00 per year; the price of single copies is 

 65 cents. Orders for service of less than a half-year will be charged at the single-copy rate, ^f Postage is 

 prepaid by the publishers on all orders from the United States, Mexico, Cuba, Porto Rico, Panama Canal 

 Zone, Republic of Panama, Hawaiian Islands, Philippine Islands, Guam, Samoan Islands, Shanghai. 

 Tf Postage is charged extra as follows: For Canada, 30 cents on annual subscriptions (total $4.30), on 

 single copies, 4 cents (total 69 cents); for all other countries in the Postal Union, 53 cents on annual 

 subscriptions (total $4.53), on single copies, 11 cents (total 76 cents). ^[Patrons are requested to make 

 all remittances payable to the University of Chicago Press in postal or express money orders or bank 

 drafts. 



The following agents have been appointed and are authorized to quote the prices indicated: 



For the British Empire : The Cambridge University Press, Fetter Lane, London, E.C. 4. Yearly 



subscriptions, including postage, 18^. 8d. each; single copies, including postage, 3*. id. each. 



For Japan and Korea: The Maruzen-Kabushiki-Kaisha, n to 16 Nihonbashi Tori Sanchome, 



Tokyo, Japan. Yearly subscriptions, including postage, Yen 9.00 each; single copies, including 



postage, Yen 1.50 each. 



For China: The Mission Book Company, 18 Peking Road, Shanghai. Yearly subscriptions, 



$4.00; single copies, 65 cents, or their equivalents in Chinese money. Postage extra, if mailed direct 



outside of Shanghai, on yearly subscriptions, 53 cents, on single copies, 11 cents. 



Claims for missing numbers should be made within the month following the regular month of 

 publication. The publishers expect to supply missing numbers free only when losses have been sustained 

 in transit, and when the reserve stock will permit. Deliveries are not guaranteed within the war zones of 

 Europe, nor in other countries where transportation is disturbed by conditions incident to war. 



Business correspondence should be addressed to The University of Chicago Press, Chicago, 111. 



Communications for the editors and manuscripts should be addressed to the Editors of The 

 Journal of Geology, the University of Chicago, Chicago, 111. 



Contributors are requested to write scientific and proper names with particular care and in citations 

 to follow the form shown in the pages of the Journal. 



Separates, if desired, must be ordered in advance of publication. Separates of leading articles will be 

 printed as ordered, of which 50 (without covers) will be furnished gratis, the actual cost of the remainder 

 (and covers, if desired) to be paid for by the author. The actual cost may vary, and will depend upon 

 the amount of work in re-making the pages into forms, presswork, paper, binding, etc. . Separates 

 containing half-tones may be expected to cost somewhat more, the increase depending upon the number 

 of cuts and the amount of work required upon them. 



Entered as second-class matter, March 20, 1893, at the Post-office at Chicago, HI., under the Act of March 3, 1879 



