1873.] On the Currents of the Dardanelles and Bosphorus. 387 



a well-marked genus or subfamily of Macropodidae are illustrated by 

 fossils, on which are founded a genus Procoptodon, and the species Proc. 

 Pusio, Proc. Goliah, and Proc. Rapha. The paper concludes with the descrip- 

 tion of a considerable part of a fossil cranium indicative of the largest form 

 of kangaroo hitherto found ; for the subgenus and species so indicated 

 the author proposes the name Palorchestes Azael. 



The illustrations of the paper form the subjects of nine 4to Plates. 



IX. " Observations on the Currents and Undercurrents of the 

 Dardanelles and Bosphorus,, made by Commander J. L. 

 Wharton, of H.M. Surveying- Ship ' Shearwater/ between the 

 months of June and October, 1872/'' From a Report of that 

 Officer to the Hydrographer of the Admiralty. Communi- 

 cated by Admiral Richards, C.B., V.P.R.S. Received May 7, 

 1873. 



There is a general now of the Black-Sea water through the Bosphorus, 

 Marmara, and Dardanelles to the Mediterranean, probably caused by the 

 combination of three things : — first, the prevalence of JNT.E. winds in the 

 Black Sea ; secondly, the excess of water received from the large rivers 

 over the amount lost by temperature at some seasons ; and, thirdly, the 

 difference of specific gravities in the two seas. 



Of these, observation goes to prove that the wind has by far the greatest 

 influence. 



There is as general a countercurrent setting up under the surface- 

 stream, in an opposite direction, from the Mediterranean to the Black 

 Sea. This seems to be dependent on the surface-current ; for when the 

 latter is slack, the undercurrent is slack likewise. 



Dardanelles. 



Erom observations made from 14th June to 30th October 1872. 



The ordinary direction of the surface-current in mid-stream is S.W., 

 or " down " the straits, with the wind, which blows from the opposite 

 quarter for three parts of the year ; but when a S.W. wind has lasted a 

 few days and forced its way through the straits from one end to another, 

 the current will run in the opposite direction, but never so strongly as 

 the S.W. current. 



Wherever a point juts out into the straits, or a turn occurs, counter- 

 currents run up strongly inshore on their lee sides, as might be expected ; 

 and, generally speaking, with the exception of those places where the 

 straits are narrowed by two points opposite to one another, either slack 

 water or a slight eddy exists, on either shore, for a short distance from 

 the coast. 



