144 Geological Society, 



fiiaion of the shale, two narrow vitreous bands of different origin 

 "being thus developed side by side on each side of the vein, the 

 colourless bands representing the chilled margins of the vein, the 

 brown bands the fused surfaces of the walls of shale. The author 

 only suggested this as a plausible explanation of the microscopic 

 phenomena. An analysis of portion of one of these whin veins 

 with its adherent tachylyte, made by Mr. Philip Holland, was 

 appended to the paper. 



2. " The Descent of Sonninia and of Hammatoceras" By S. S. 

 Buckman, Esq., F.G.S. 



3. " Notes on the Bagshot Beds and their Stratigraphy." By H. 

 G. Lyons, Esq., R.E., F.G.S. 



The author deplored the necessity of quitting the area which he 

 had studied before completing his observations, and wished to place 

 his results at the disposal of other workers. 



In a previous paper he had discussed the beds at their southern 

 outcrop, over a small area, and showed that there the Bagshot and 

 London Clay strata remained of constant thickness, and dipped 

 northwards at an angle of about 2^°. He had since examined the 

 country between Aldershot and Ascot over an area of about 15 

 miles square, and attempted by contouring the surface of the Middle 

 Bagshot beds (which showed a nearly constant thickness of 60 feet 

 over the area), to give the form into which the beds had been 

 pushed by the different slight flexures which might occur. After 

 giving details of the heights at which this surface was found, 

 he concluded that an anticlinal of which the axis pointed upon 

 Windsor Castle, appeared to pass through the Swinley and Wel- 

 lington-College area, and probably to Hazeley Heath ; and that a syn- 

 clinal started by Minloy and Hawley, and ran by the Royal Albert 

 Asylum, Gordon Boys' Home, upon Ongar and Row Hills, and 

 Woburn Hills ; and that another anticline ran to St. George's Hill, 

 Weybridge. 



The author had attempted to map the southern and eastern 

 limits of the Upper Bagshot beds, and claimed a much greater 

 extent for these beds in those directions than had been assigned by 

 the members of the Geological Survey. The outcrop of the beds 

 was described in some detail, and the occurrence of outliers on 

 Knaphill Common, by Donkey Town, on Chobham Common, and 

 on Staples Hill was noted. 



4. " Description of some new Species of Carboniferous Gastero- 

 poda." By Miss Jane Donald. 



5. " OystecJiinus crassus, a new Species from the Radiolarian 

 Marls of Barbadoes ; and the evidence it affords as to the Age and 

 Origin of those Deposits." By J. W. Gregory, Esq., F.G.S. 



