396 Scientific Intelligence. 



waves and current action to the work they do. Then he takes 

 up the terminology and classification of shore types, and this 

 leads into a long account of the development of shorelines. 

 Finally there is a chapter on shore ridges and their significance, 

 and another on the various kinds of shore structures made by 

 the waves, as ripple-marks, etc. The book is easily understood 

 by the careful reader, as each chapter opens with an "advance 

 summary" and closes with a "resume." 



We are told that waves 40 feet high are of fairly frequent 

 occurrence in the open oceans, that a jar brought up from a 

 depth of 220 feet had gravel in it the size of a hazelnut, and that 

 a lobster pot at 180 feet depth had stones washed into it weigh- 

 ing up to one pound. "We may take 600 feet as the limiting 

 depth of ordinary wave disturbance, although Cornish set 900 

 feet as the limit for the largest recorded waves" (225). Ripple- 

 marks are sometimes made by either waves or currents in fine 

 sand at a depth even greater than 600 feet. A single storm has 

 removed from the Chesil bank in England as much as 4-5 million, 

 tons of shingle," and before it subsided one half of it was moved 

 back again. The great wave-cut platform off Norway has a 

 maximum width of 40 miles. 



Wave base is "the imaginary plane down to which wave action 

 tends continually to reduce the lands." Johnson adds that "A 

 cycle of wave erosion ends, therefore, when all the land is 

 reduced to a plane surface about 600 feet below sealevel." It 

 is safe to say that such a completed cycle is rarely, if ever, 

 attained even on the land facing the great oceans, while the 

 inner shallow seas, like Hudson Bay and the Baltic, do not have 

 waves of anywhere near the depth penetration and therefore not 

 of the eroding strength of those of the deep oceans. On the 

 other hand, if the ocean waves are cutting planes whose surface 

 is ' ' about 600 feet below sealevel, ' ' the reviewer can not under- 

 stand why there should be so much material lying upon the 

 continental shelves. Can the explanation be that the eroded 

 material of the land is being delivered upon the deeper parts 

 of the shelves faster than the great waves can carry it seaward ? 

 If so, then wave base can not be eroded down to 600 feet of 

 depth in most places. c. s. 



2. World-Power and Evolution; by Ellsworth Hunting- 

 ton. Xew Haven, Yale University Press, 1919, 287 pp., 30 text 

 figs. — A most interesting and readable book for biologists, pale- 

 ontologists, physicians, and statesmen. The underlying thesis 

 is that organic evolution and maximum health are largely con- 

 ditioned by a favorably changing environment, chiefly climatic. 

 Under favorably cool to even cold seasonable climates, man is 

 energized, and with plenty of food and water he is stimulated 

 to idealism and a higher civilization that is bound to be spread 

 among the less well situated. The book is thought-provoking in 

 its explanation as to why Germany is so dominant in action, why 



