'746 Geological Society : — 



June 4th.— Mr. G. W. Lamplugh, F.R.S., President, 

 in the Chair. 



The following communications were read : — 



1. 'On the Dentition of the Petalodont Shark, Climaxodus? 

 By Arthur Smith Woodward, LL.D.,F.R.S., P.L.S., F.G.S. 



2. ' A New Theory of Transportation by Ice : the Raised 

 Marine Muds of South Victoria Land (Antarctica).' By Frank 

 Debenham, B.A., B.Sc, F.G.S. 



A series of deposits of marine muds are found on the surface 

 of floating 'land-ice' in the deep bays of Boss Sea (Antarctica). 

 Similar deposits are also found on land up to a height of 

 200 feet, in some cases on old ice, in other cases on moraine. 

 The deposits are briefly described, and former theories concerning 

 them are discussed. 



A new theory is put forward, prefaced by an account of the 

 nature of the typical ice-sheet which bears them. The upper 

 surface of the sneet is known to suffer a net annual decrease, 

 and evidence is given to show that the lower surface has a net 

 increase by freezing from below. 



The theory is that the sheet will freeze to the bottom in severe 

 seasons, and enclose portions of the sea-floor. Owing to the 

 method of growth of the sheet by increments from below, the 

 enclosed portions will ultimately appear on the surface, thus 

 being raised vertically as well as translated horizontally. 



The application of the theory to other localities is briefly 

 sketched, with especial reference to the shelly moraines of Spits- 

 bergen and the shelly drifts of the glacial deposits of Great 

 Britain. The general results of such a method of transportation 

 are shown uo be the raising of marine deposits above their initial 

 level, the preservation of the organisms, the deposition of small 

 patches of muds with ordinary supra-glacial moraine, and the col- 

 lection of remains of fauna from different depths in one horizon. 



June 25th.— Mr. G. W. Lamplugh, F.B.S., President, 

 in the Chair. 



The following communications were read : — 



1. ' Outlines of the Geology of Southern Nigeria (British West 

 Africa) with especial reference to the Tertiary Deposits.' By 

 Albert Ernest Kitson, C.B.E., F.G.S., Director of the Geological 

 Survey of the Gold Coast. 



The oldest rocks in Southern Nigeria comprise a series of 

 quartzites, schists of various kinds, blue and white marble, grey 

 limestones, altered tuffs and lavas, amphibolites and gneisses. Their 

 strike varies from west-north-west and east-south-east to north-east 

 and south-west. They occur in the north-western portion of the 

 country (Yorubaland), north of lat. 7° N., and in the Oban-Hills 

 region in the east. They may be classed provisionally as Pre- 

 Cambrian. Intruded into these are large masses of granites of 

 various kinds, syenite and diorite, with pegmatite- and aplite-dykes. 

 In some parts these rocks have shared in the dynamic alteration 



