714 ABSTRACTS OF PAPERS 



employed. The dictionaries define "littoral" as the zone of shore between high 

 and low tide. Such a zone has definite geologic and biologic characteristics. 

 It seems unfortunate, then, that a loose and vague use of this word should be 

 given scientific sanction merely because certain zoologists have so employed it. 



There is also a question if for present purposes so much use need be made 

 of the Greek language for terms but seldom used. For example, "shallow sea 

 deposits" is a term perfectly clear and quite as sharp as the Greek form used 

 in this classification. A system of classification should require as little mem- 

 orizing of unfamiliar terms as possible in order to command its acceptance-. 



On one division of Professor Grabau's classification I wish to place emphasis. 

 It may have seemed that his divisions of "rafted material" illustrated pushing 

 a classification to a futile extreme. On the contrary. I have been impressed 

 with Darwin's statement that at a distance of several hundred miles from the 

 shores of the Sahara the water was perceptibly colored by dust blown from the 

 desert. Off the leeward shores of Australia the same phenomenon has been 

 noted ; there the air and water are at times laden with dust. The abundance 

 of finer clastic material which is carried in this way suggests that a consider- 

 able source of the clay of certain ancient argillaceous limestones may be from 

 wind-borne dust — eolian deposits of the sea. 



Material rafted by trees and ice must also contribute perceptibly to certain 

 deposits, when we consider the slowness of accumulation on the bottom of the 

 deep open seas of water-borne material settling from suspension. The Challen- 

 ger expedition in one dredge-load from the central Pacific recovered 1,500 

 sharks' teeth and 50 ear bones of whales, which means that if all the life were 

 put back into the sea which had existed during this accumulation many sharks 

 and whales would have to occupy at the same time the narrow vertical prism 

 of water above this piece of bottom. In view of this slowness of natural depo- 

 sition, man has become, as in many other regions of the earth, an important 

 geological agent. The oxidized and inorganic debris which he throws over- 

 board from ships must already mark out the steamer lanes across, especially 

 the abyssal ocean bottoms. The unalterable materials which he contributes 

 most abundantly to the deposits of the sea are coal ashes, broken dishes, and 

 bottles. These are being permanently incorporated in the crust. They will 

 endure long after the monuments which he erects above baselevel shall have 

 crumbled and been removed by erosion. These geologic records will be up- 

 lifted and exposed in places by future crustal movements and shall link the 

 distant future to that past which is the present. It is seen in the light of these 

 facts that the name being recorded most widely and indelibly on the earth at 

 the present time is the name of him who made Milwaukee famous. 



POSTGLACIAL EARTH MOYEMEXTS ABOUT LAKE ONTARIO AXD THE SAINT 



LAWRENCE RIVERA 



BY J. W. SPEXCER 



Published as pages 217-228 of this volume. 



1 Presented at the meeting under the title "Extended determination of postglacial earth 

 movements from the Lake region to the Saint Lawrence Valley." 



