192 Kindle — Note on Bottom Currents in Lake Ontario. 



Art. XI. — Note on Bottom Currents in Lake Ontario ;* 



by E. M. Kindle. 



The observations which are presented in this paper relate 

 to data which were obtained as an incidental result of the study 

 of certain phenomena associated with sedimentation. They 

 were made while using specially devised apparatus for the mak- 

 ing of ripple-mark molds under water. It was not foreseen that 

 bottom currents would be met with in connection w T ith the 

 investigation of the problems of sedimentation which were 

 undertaken. The writer was, therefore, not provided with instru- 

 ments for precise measurement of the velocity of the subsur- 

 face currents encountered. For the opportunity to observe 

 these and other factors in the general problem of sedimenta- 

 tion in Lake Ontario, the writer is indebted to the very liberal 

 policy of Mr. R. W. Brock, former Deputy Minister of the 

 Department of Mines and Director of the Geological Survey 

 of Canada, in initiating work in this important and little 

 developed field of investigation. 



The surface currents of Lake Ontario, in connection with 

 those of the other Great Lakes, were made the subject of an 

 elaborate investigation! some years ago by tabulating of the 

 drift records of several hundred bottles thrown overboard at 

 numerous and widely distributed points. Harrington's investi- 

 gation of the lake currents relates almost entirely to the "body 

 currents" or those connected with the general outflow or set of 

 the water toward the outlet and their modifications by surface 

 currents due to the prevailing winds. The extremely slow 

 movements of these currents, varying from four to twelve miles 

 per day, which Harrington was able to demonstrate and chart, 

 renders them of comparatively slight importance as geologic 

 agents. They could be effective in transporting only sediments 

 in which the minute size of the particles made them nearly 

 intangible elements of the products of sedimentation. Wholly 

 independent of these gentle surface and outflow currents, there 

 are in Lake Ontario subsurface and bottom currents which are 

 at times effective and powerful agents for the transportation of 

 sediments. Their erratic appearance and behavior is the result 

 apparently of the varying wind and barometric pressures which 

 produce them. Their subsurface operation and irregular per- 

 iods of activity render them difficult of investigation but 

 extremely important when considered as factors in the sorting 

 and transportation of sediments. Their movement along the 



* Published with the permission of the Director of the Geological Survey 

 of Canada. 



f Currents of the Great Lakes, U. S. Weather Bureau, Bull. B., 1894, by 

 Mark W. Harrington. 



