174 Geological Society : — 



Chapter XII. deserves severe criticism. It seems a pity that the 

 author did not make a more exhaustive study of this subject before 

 proceeding to write on it. Many standard methods which have 

 given excellent results are omitted, while Mr. Mordey's " thermo- 

 meter " method is duly mentioned. 



The section on polyphase induction motors appears capable of 

 considerable improvements. The Heyland diagram for the in- 

 duction motor, which is so freely used by almost every continental 

 writer on the subject, is not even mentioned, and in place of it 

 we have purely analytical investigations which are not likely to 

 appeal to the reader. 



Altogether, the second half of the book is much less satisfactory 

 than the first, and we hope that in a future edition the blemishes 

 which we have pointed out will be removed. There is ample room 

 for a book of this kind, and we believe that, in spite of its defects, 

 it will prove extremely useful to a large circle of readers. 



XVII. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from vol. iii. p. 554.] 

 January 8th, 1902.— J. J. H. Teall, Esq., M.A., Y.P.P.S., 

 President, in the Chair. 

 ,r PHE following communications were read : — 

 -*■ 1. ' A System of Glacier-Lakes in the Cleveland Hills.' By 

 Percy Pry Kendall, Esq., P.G.S., Lecturer in Geology at the York- 

 shire College, Leeds. 



After referring to existing l extra-morainic ' lakes, such as the 

 Miirjelen See and those of the Chaix Hills, the author proceeds to 

 -deal with the criteria for the recognition of such lakes. These 

 include beaches, deltas, floor-deposits, and overflow-channels. Shore- 

 scarps are common in Cleveland, but beaches are rare or absent, 

 the reason being in part that stability was rarely secured owing to 

 the overflows being over soft Jurassic strata. Deltas also are not 

 common. The floor-deposit of lakes may be distinguished from 

 river- alluvia by the fact that the lamination is close and regular, 

 but, being parallel to the subjacent surface, it may be highly 

 inclined. On the other hand, alluvia are laid down on horizontal 

 surfaces, but rarely show good lamination. Overflow-channels are 

 grouped into four main types : ' direct overflows/ which trench the 

 main watershed of a country ; ' severed spurs,' across the spurs of 

 the main watershed ; ' marginal overflows,'* at first merely a shelf 

 cut in the hillside, but subsequently developed into an actual gorge ; 

 and 'in-and-out channels,' or crescentic valleys excavated in the 

 face of a hill by water flowing round a lobe of ice. Such overflows 

 are independent of the natural drainage ; they have at first a slight 

 and then a steep fall, and in section they have steep sides and flat 

 floors. The meanders of the valleys and the run of the contouring 

 also possess special features, and the valleys rarely or never receive 

 any considerable tributaries. 



