PROCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY OF LONDON. 



1829. No. 12. 



May 15. — Wm. Babington, Esq., of St. John's Wood, Regent's 

 Park 5 and Henry Humphry Goodhall, Esq., of the East India House, 

 were elected Fellows of this Society. 



The reading of a paper, " On the Hydrographical Basin of the 

 Thames, with a view more especially to investigate the causes which 

 have operated in the formation of the valleys of that river, and its 

 tributary streams ; " by the Rev. W. D. Conybeare, F.G.S., F.R.S., 

 &c, &c. was begun. 



June 5. — William Lonsdale, Esq., Lieut. 4th Reg. of Infantry, and 

 late Honorary Curator of the Bath Philosophical Institution, &c, &c.; 

 the Rev. Thos. Thorp, M.A., Fellow of Trinity College, Cambridge; 

 the Right Rev. John Matthias Turner, D.D., Lord Bishop of Calcutta; 

 David Douglas, Esq., F.L.S., of Turnham Green ; Thos. Erskine 

 Perry, Esq., B.A., of Trinity College, Cambridge, and Whitehall ; 

 and Charles Earl, Esq., — were elected Fellows of this Society. 



The reading of a paper, On the Valley of the Thames, by the Rev. 

 W. D. Conybeare, F.G.S., F.R.S., &c, &c, (begun at the last meet- 

 ing,) was concluded. 



The author has selected this river, not only as being the principal 

 one of the island, but further as exhibiting valleys exclusively the result 

 of denudation, and therefore better suited to illustrate that operation 

 than valleys of more complicated origin, in the formation of which 

 the elevation and dislocation of the strata have co-operated. 



He first offers some introductory remarks on the opposite theories 

 of the fluvialist and diluvialist, the former ascribing such denudations 

 exclusively to the operation of the streams actually existing, or rather 

 to the drainage of the atmospherical waters falling on the districts, 

 which it is supposed have become thus deeply furrowed by the gra- 

 dual erosion of these waters, continued through a long and indefinite 

 series of ages ; the latter contending that such a cause is totally in- 

 adequate to the solution of the phenomena, and maintaining that they 

 afford evidence of having been produced by violent diluvial currents. 



He proceeds to distinguish several different geological epochs, at 

 which it is probable that currents must have taken place calculated 

 to excavate and modify the existing surface. I. In the ocean, be- 

 neath which the strata were originally deposited. II. During the 

 retreat of that ocean. III. At the periods of more violent disturbance, 

 which are evidenced by the occurrence of fragmentary rocks, the 

 result of violent agitations in the waters of the then existing ocean 

 propagated from the shocks attendant on the elevation and dislocation 



