[ 193 ] 



XXIII. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 124.] 



April 16, 1890.— J. W. Hulke, Esq., E.R.S., Vice-President, 



in the Chair. 



rPHE following communications were read : — 

 -*- 1. " On the disturbed Rocks of North-western Germany." By- 

 Prof. A. von Konen, Eor.Corr.G.S. 



After referring to the disturbances of Palaeozoic times, the author 

 commented upon the Miocene dislocations of the Harz, Rhineland, 

 Westphalia, and Nassau, which have a N.W.-S.E. strike, varying 

 to N.-S. or E.-W., and which are similar to postglacial dis- 

 locations. 



He briefly discussed the origin of these dislocations, and noticed 

 their peculiarities, and proceeded to consider the relationship of the 

 intruded basalts to the disturbances, supposing that during the pro- 

 cess of faulting the earth's crust was pressed downward along 

 synclinal lines and that the basaltic magma escaped upwards through 

 the inverted funnel-shaped synclinal fissure. 



Comparison was made between these Tertiary basalts and the pro- 

 ducts of modern volcanic eruptions, and it does not appear to the 

 author to be unlikely that the cause of the outflow of many of the 

 lavas in the latter was similar to that which produced the extension 

 of the Tertiary basaltic rocks. 



2. " On the Origin of the Basins of the Great Lakes of America." 

 By Prof. J. W. Spencer, M.A., Ph.D., E.G.S., State Geologist of 

 Georgia. 



Erom the study of the hydrography of the American lakes, from 

 the discovery of buried channels revealed by borings, from the 

 inspection of the glaciation of the lake-region, the consideration 

 of the late high continental elevation, and the investigation of 

 the deformation of old water-levels, as recorded in the high-level 

 beaches, the explanation of the Origin of the Basins of the Great 

 Lakes becomes possible. 



The original Erie valley drained into the extreme western end of 

 Lake Ontario — the Niagara river being modern — by a channel now 

 partly buried beneath drift. Lake Huron, by way of Georgian Bay, 

 was a valley continuous with that of Lake Ontario ; but between 

 these two bodies of water, for a distance of about 95 miles, it is now 

 buried beneath hundreds of feet of drift. The old channel of this 

 buried valley entered the Ontario basin about twenty miles east of 

 Toronto. The northern part of Lake-Michigan basin was drained 

 into the Huron basin, as at present ; whilst the southern basin of 

 that lake emptied by a now deeply drift-filled channel into the south- 

 western part of Huron. The buried fragments of a great ancient 

 valley and river, and its tributaries, are connected with submerged 

 channels in Lake Huron and Lake Ontario, thus forming the course of 



Phil. Mag. S. 5. Vol. 30. No. 183. August 1890. 



