Geology of the South of Westmoreland. 555 



retrocession must have proceeded much more slowly for about a mile, 

 or to the Whirlpool, where a small fall of 6 or 8 feet still marks the 

 place of the highest beds of the sandstone. After, Mr. Lyell says, 

 the cataract had remained nearly stationary for ages at this point, it 

 next receded more rapidly for two miles, having soft red marl 70 feet 

 thick to erode its way through ; but beds of greater solidity, con- 

 sisting of grey and mottled sandstone and Protean limestone, amount- 

 ing in all to 30 or 40 feet, then offered a greater resistance, and con- 

 tinued to retard the backward movements of the Falls, the Protean 

 limestone occurring at the base of the present precipice. 



Lastly, the author offers some observations respecting the future 

 retrocession of the Falls, quoting the opinions entertained by 

 Mr. J. Hall (Report for 1838) on the effects which the strata 

 above the existing cataract will have on the progress of the river, 

 and pointing out results similar to those given by Mr. De la Beche 

 in his ' Manual of Geology.' But all predictions, Mr. Lyell says, 

 regarding the future history of the Falls may be falsified by the 

 disturbing agency of man. Already a small portion of the waters 

 of Lake Erie is carried off to supply the Welland canal, and another 

 canal on the American side of Niagara ; and numerous mill-races 

 have been projected and others will be required along both sides of 

 the river, as the population and wealth of the country increase. 

 Many cities also, situated to the eastward of the great escarpment 

 and at a lower level, may in after times borrow water from Lake 

 Erie, especially as the continued felling of the forests causes streams 

 which were formerly constant to become dry in summer; and it 

 must not be forgotten that Lake Michigan has lately been made by a 

 cutting to feed the Illinois river, and that whatever quantity of water 

 is abstracted from the upper lakes is taken away from the Niagara. 



Feb. 2nd, — " Sketch of the Geology of the South of Westmore- 

 land." By Daniel Sharpe, Esq., F.G.S. 



The object of this communication, the author says, is to describe 

 the Silurian rocks and the old red sandstone of the south of West- 

 moreland, to define approximative^ their geographical boundaries, 

 and to compare their lithological structure and stratigraphical phe- 

 nomena with the equivalent formations previously noticed in other 

 parts of the kingdom. 



The author, in alluding to the published labours of those who 

 preceded him in the same district, mentions the memoir of Mr. J. 

 Phillips on a group of slate rocks between the Lune and Wharf, 

 Prof. Sedgwick's on the Cumbrian mountains f, Mr. J. G. Mar- 

 shall's on a section between the Shap granite and Casterton Fell J, 

 and Prof. Sedgwick's Geological Map of Westmoreland ; also the 

 abstract of his memoirs on the English stratified rocks inferior to 

 the old red sandstone §. 



• Geol. Trans., 2nd Series, vol. hi. part i. p. 1, 1829. 

 t Ibid, vol. iv. part i. p. 47, 1835. 

 % Proceedings of British Association for 1839. 



§ Proceedings, vol. ii. p. 675 [Phil. Mag. S. 3. vol. xiii. p. 299.] ; Athe- 

 naeum, No. 736; Proceedings, vol. hi. p. 541. 



