7° 



NEW YORK STATE MUSEUM 



cided lack of horizontal uniformity and continuity. A lower 

 water level should have been steadier than the superior or original 

 level for the reason that the outlet was more mature and the lake 

 larger in area. The lower Warren bars are sufficiently strong to 

 have great continuity and uniformity of level if their formative 

 conditions had favored it, but no separate or distinct water plane 

 can be selected among the lower Warren bars. 



4 The idea that the inferior Warren bars are chiefly the normal 

 product of offshore waterwork in a lake of long life with very slowly 

 falling surface would seem to harmonize the facts of variable 

 altitude, horizontal discontinuity, generally finer material, and 

 as a rule more rounded or flatter summits. 



The incomplete data gathered in the table [p. 65] indicate that 

 a depth of 25 feet below the upper bar is the limit of effective bar 

 construction. This figure may be reduced by whatever lowering 

 of the surface level is to be allowed, and 5 feet may be taken out for 

 the hight above the water surface of storm bars of coarse material. 



The mechanics of the deeper work of the water is not well under- 

 stood, but theoretically it would appear that the first offshore bar 

 must lie below (in depth) and beyond (in horizontal distance) the 

 zone of action occupied by the heavy waves which build the surface 

 or marginal bar. The vertical distance between the marginal and 

 the nearest submerged bar is greater (within limits) as the hori- 

 zontal distance is less. It would appear, therefore, that normally a 

 striking vertical interval might lie between a heavy marginal ridge 

 and the first submerged bar, sometimes suggesting two distinct 

 water planes. 



It is apparent that the bar elements will vary with several factors : 

 the topography and slope of the bottom, the volume and character 

 of the detritus, the exposure to winds and depth of water, and the 

 effectiveness of shore currents. It is not now possible to apply 

 these principles to the case in hand. The factors in waterwork 

 are so delicately adjusted -and (to our sight) so capricious in their 

 operation that they are elusive to study. It is very desirable that 

 an examination of existing lakes and seas should be made with 

 reference to the offshore constructive features. And we specially 

 need criteria for distinguishing phenomena produced in slowly 

 rising water from those produced in slowly falling water. 



The absence of inferior bars along the Whittlesey shore may be 

 due to the steeper slope, the more variable and perhaps rising 

 water level, and the brevity of the life of the lake. The last factor 

 is the probable explanation of the simplicity of the Warren shore 

 east of Crittenden. 



