PROCEEDINGS 



OF THE 



GEOLOGICAL SOCIETY OF LONDON. 



SESSION 1889-90. 



November 6, 1889. 



W. T. Blanfokt), LL.D., F.R.S., President, in the Chair. 



The Uev. D. Charles Evans, Menai Bridge, was elected a Fellow 

 of the Society. 



The List of Donations to the Library was read. 



The following communications were read : — 



1. " Contributions to our Knowledge of the Dinosaurs of the 

 Wealden and the Sauropterygians of the Purbeck and Oxford 

 Clay." By E. Lydekker, Esq., B.A., F.G.S. 



2. " Kotes on a ' Dumb Fault ' or * Wash-out ' found in the 

 Pleasley and Teversall Collieries, Derbyshire." By J. C. B. Hendy, 

 Esq. (Communicated by the President*. ) 



The *' Top Hard " Seam of the district is being worked in these 

 collieries at a depth of 500 yards, where it has an average thickness 

 of 5 feet, with a band of cannel in the middle. In the working it was 

 found that the coal began to thicken, until it became double the 

 usual size, the cannel also increasing in the " Top Seam," but in 

 the Lower Seam running out altogether. 



This double thickness of coal continued till the " wash-out " 

 was reached, when both coal and shaly roof disappeared, the space 

 being replaced by sandstone similar to that of the beds overlying 

 the shale. The clay floor of the Lower Seam had not been much 

 interfered with, and this was followed for 60 yards, when the 



* This paper has been withdrawn by permission of the Council. 

 VOL. XLVI. a 



