378 



PEOCEEDIKGS or THE GEOLOGICAL SOCIETY. [Junc 18, 



prominent are about an inch wide, and extend several yards in a 

 IDcrfcctly straight line. In appearance they seem to have been caused 

 by the passage of some heavy body across the rock; and as ice 

 seems the only agent possible to produce the result, the grounding 

 of icebergs in the '' Glacial Sea" is probably the cause. 



Polished striated boulders and small stones are common in the 

 overlying " Boulder-clay," and shells very rare. 



Note. — Since making the above communication, I have found very 

 distinct ice-grooves at Oxton, Cheshire, half a mile S.E. from Elay- 

 brick Hill. The direction of the striations is N. 30° W., and the 

 elevation is about 120 feet above high-water level. — October 8, 1862, 

 G. H. M. 



June 18, 1862. 



John Gumming, Esq., 7 Montagu Place, Russell Square, and 

 William Topley, Esq., of the Geological Survey of Great Britain^ 

 Colchester "Villas, Lewisham Road, were elected Fellows. 



The following communications were read : — 



1, Oyi the Mode oe Formation of some of the River-vallets in the 

 South of Ireland. By J. Beete J"uKES,Esq., M.A., F.R.S., F.G.S., 

 Local Director of the Geological Survey of Ireland, &c, 

 [Plates XIX. & XX.] 

 Contents. 



Introduction. 



Part I. Physical Structure of the South 



of Ireland. Former Extension of 



the Upper Paleozoic Kocks. 

 Part II. The Existing Eiver-yaUeys of 



the South of Ireland. 



1. The Eiver Shannon. 



2. TheEiversBarrow,Nore,andSuir. 



3. The Eiver Blackwater. 



4. The Eiver Lee. 



5. The Eiver Bandon. 

 Part III. Pormation of the Transverse 



Eavines. 

 A. The Eavines not caused by Dis- 

 turbance. 



Introduction. — The determination of the method by which the sur- 

 face of the land has been carved out of the subjacent rock into its 

 present form is a geological problem which has not yet been solved, 

 except in a very general way. The most important contribution 

 towards this solution is the paper by our President, Professor Ram- 

 say, " On the Denudation of South Wales and the adjacent Counties 

 of England," in the first volume of the ' Memoirs of the Geological 

 Survey,' in which the amount of denudation is proved by means of 

 the accurate sections constructed by the Survey. 



B. Eelations between the Actions of 

 Denudation and Disturbance in 

 the Production of the Form of the 

 Surface of tlie Ground. 



C. Proposed Explanation of the 

 Formation of the Transverse Val- 

 leys. 



a. Eiver Bandon. 



b. Eiver Lee. 



c. Eiver Blackwater. 



D. Application of this Explanation 

 to the Eavines of the Shannon and 

 of the Barrow, Nore, and Suir. 



Postscript. 



