SCIENCE 



Editoeial Committee : S. Newcomb, Mathematics ; R, S. "Woodward, Mechanics ; E. C. Pickering, As- 

 tronomy ; T. C. Mendenhall, Physics ; R. H. Thueston, Engineering ; Iea Remsen, Chemistry ; 

 J. Lb Conte, Geology; W. M. Davis, Physiography; O. C. Maesh, Paleontology; W. K. Beooks, 

 Invertebrate Zoology ; C. Haet Meeeiam, Vertebrate Zoology ; S. H. Scuddee, Entomology ; 

 N. L. Beitton, Botany ; Heney F. Osboen, General Biology ; H. P. Bowditoh, 

 Physiology ; J. S. Billings, Hygiene ; J. McKeen Cattell, Psychology ; 

 Daniel G. Beinton, J. W. Powell, Anthropology. 



Friday, October 25, 1895. 



CONTENTS: 



Vieiv of the Ice Age as Two Epochs, the Glacial and 

 Cliamplain: Waeeen Upham 529 



Helium and Argon: H. N. Stokes 533 



Economics of Engineering PiMic Works : Heney 

 N. Ogden 539 



Marine Laboratory of the U. 8. Fish Commission at 

 Wood's Hole: J. I. Peck 543 



Geography at the British Association: Eobeet 

 Hugh Mill 545 



Scientific Notes and Neios : — 547 



Tlie Smithsonian Exhibit at Atlanta ; General. 



Educational Notes and News 551 



Correspondence: — 552 



A Few More Words in Regard to the New Biblio- 

 graphical Bureau : Heebeet Haviland Field. 

 27(6 Dogmatism of Science : Geoege M. Gould. 

 T!w Inverted Image on the Retina Again : J. B. 

 Woodwoeth ; J. McK. C. ' Crying with Two 

 Ears:' "W. H. FiSHBUEN. Inaccurate Zoology : 

 Theodoee D. a. Cockeeell. 



Sciemtific Literature : — 557 



Verworn's Allgemeine Pliysiologie : Chaeles S. 

 Minot. Trevor- Baitye's Ice-bound on Kolguev : 

 William Libbey, Jr. 3Iarkham on Major 

 James Rennell and the Rise of 3Iodern English 

 Geography : W. M. D. Oeuvres Ophtalmo- 

 logigues de Thomas Young : Charles Henry. 



Societies and Academies : — 563 



The Entomological Society of Washington : L. O. 

 Howard. The New York Academy of Sciences : 

 Wm. Hallock. 



New Books 564 



MSS. intenaed for publication and books, etc., intended 

 for review should be sent to the responsible editor, Prof. J. 

 McKeen Cattell, Garrison on Hudson, N. Y. 



Subscriptions and advertisements sliould be sent to Science, 

 1 N. Queen St., Lancaster, Pa., or 41 East 49th St., New York. 



VIEW OF THE ICE AGE AS TWO EPOCHS, 

 THE GLACIAL AND CHASIPLAIN^ 



The present paper supplements that pre- 

 sented by the author in the Proceedings of 

 this Association a year ago, which showed 

 the Quaternary era as divided into the La- 

 fayette, Glacial and Recent periods. The 

 Glacial period or Ice age is here more par- 

 ticularly reviewed, and is found divisible 

 into two parts or epochs, the first or Glacial 

 epoch being marked by high elevation of 

 the drift-bearing areas and their envelop- 

 ment by vast ice sheets, and the second or 

 Champlain epoch being distinguished by the 

 subsidence of these areas and the departure 

 of the ice with abundant deposition of both 

 glacial and modified drift. Epeirogenic 

 movements, first of great uplift, and later 

 of depression, are thus regarded as the basis 

 of the two chief time divisions of the Ice 

 age. Each of these epochs is further divided 

 into stages, marked in the Glacial epoch by 

 fluctuations of the predominant ice accumu- 

 lation, and in the Champlain epoch bj' suc- 

 cessively diminishing limits of the waning 

 ice sheet. 



Studies by many observers have shown 

 that both in JSTorth America and Europe the 

 border of the drift along the greater part of 

 its extent was laid down as a gradually at- 

 tenuated sheet ; that the ice retreated and 

 the drift underwent much subaerial erosion 



* Read before the American Association for the 

 Advancement of Science, Sept. 2, 1895. 



