Notices of Memoirs — A. JDelehecque — The Engadine Lakes. 565 



The origia of the Mediterranean is separately dealt with, and the 

 -cause of the unequal distribution of land and sea in the northern and 

 southern hemispheres is discussed. 



Though the contraction of the ocean basins has been the maia 

 •cause of the deformation of the crust, the contraction of the con- 

 tinental areas has also had some share in the result. The tjentral 

 ridge of the Atlantic bottom may be an earth fold caused by pressure 

 of the contiguous continental masses ; but it may also be due to 

 longitudinal fissures permitting volcanic action and consequent 

 accumulation of volcanic products, the fissures in such case marking 

 the relief of tension arising from the same cause. 



The formation of secondary ridges parallel to the oceano-continental 

 margins, but at some distance towards the continental side, seems to 

 have played an important part in the evolution. Extending ocean- 

 wards in their operation they appear in some instances to have raised 

 np portions of the ocean bottom into continuity with the land surface. 

 In this way, with the aid of volcanic action, the ocean basins appear, 

 in not a few instances, to have been successfully bridged. As the 

 permanency of the master features of the globe in much their present 

 form is a necessary corollary of the theory, such bridging of the 

 ocean basins also becomes a necessary part of the theory, and is 

 fairly met on the lines indicated. 



Explaining as it does the general outlines of continents and ocean 

 basins, as well as a large number of facts both in geography and 

 geology, it is contended that the theory as sketched does represent 

 in a general way the actual process by which the permanent features 

 of the globe took origin. 



III. — On the Lakes of the Upper Engadine. By Andke 



Delbbecqub.^ 



ONE of the most striking instances of a long depression forming 

 a pass between two valleys, and occupied by a series of lakes, 

 is to be seen in the strip of land which extends between St. Moriz 

 and the Maloja. It is occupied by the four lakes of Sils, Silva Plana, 

 Lampfer, and St. Moriz, with a depth of 71, 77, 34, and 44 metres 

 respectively. The level of these lakes ranges between 1,77L and 

 1,800 metres. The lake of St. Moriz is obviously in a rock-basin. 



As to the other three lakes, an opinion concurrently prevails 

 which, though supported by the high authority of Professor Heim, 

 is believed by the author to be unjustified. It is generally thought 

 that the river Inn, weakened by the capture of some of its tributaries 

 by the river Maira, has been unable to sweep away the deposits 

 of the torrents descending from lateral valleys, and that consequently 

 its waters have been dammed up into the three lakes in question. 



An attentive survey of the region shows that, on the contrary, 

 these lakes formerly constituted a single sheet of water in a rock- 

 basin, which extended from the Maloja to the village of Lampfer, 

 in both of which places ledges of gneiss are visible, and that the 



1 Abstract of paper read before the British Association, Southport, September, 1903, 

 in Section C (Geology). 



