Reports and Proceedings — Geological Society of London. 89 



of lime or magnesia salts, thus rendering them unsuitable for use 

 in steam boilers. Others, being impregnated with sulphurous com- 

 pounds, or possessing a saline character, are only of use for cooling 

 purposes. Analyses of the waters have been made from time 

 to time, but these having been pi'epared merely for technical 

 purposes are in most cases incomplete. A comparative examination 

 of them, however, brings out some interesting points bearing upon 

 their chemical composition in relation to the rocks from which they 

 were derived. 



Kegarding the course of the underground waters supplying the 

 numerous wells sunk in the thickly-bedded (Ordovician) limestones 

 in the Island of Montreal, the authors conclude that the channels 

 through which the waters flow have the form of irregular fissures, 

 and that " there is no distinct water-bearing horizon in the form 

 of interstratified permeable beds." The proof of this is to be found 

 in the circumstance that both the supply and the character of the 

 water differ in borings in comparatively close proximity to each 

 other. The irregular course of the waters is partly influenced by 

 the presence of abundant dykes and sheets of impervious igneous 

 rocks traversing the limestone strata in every direction. 



A very moderate estimate shows that the wells already bored 

 would yield, if pumped to their full capacity, 2,500,000 gallons 

 per diem, which is nearly one-tenth of the daily average pumped by 

 the Montreal Water Works for the use of the city. 



The source of the underground water is considered to be in all 

 probability the higher portion of the plains along the flanks of the 

 Laurentian country in the north-western part of the Island of 

 Montreal. 



This valuable report is illustrated by diagrams in the text, and by 

 (1) a geologically coloured map of the Island of Montreal and its 

 vicinity, (2) a topographical map of the city of Montreal with the 

 positions of the borings, (3) graphic diagrams showing the relations 

 of certain groups of wells in the city of Montreal and its vicinity. 



Author H. Foord. 



:E^:E]:F'OI^Ts .a.istid I^I^OGE!E]IDI3^^<3-s. 



Geological Society of London. 



'!.— December 20th, 1905.— J. E. Marr, Sc.D., F.E.S., President, in 

 the Chair. The following communications were read : — 



1. " The Highest Silurian Eocks of the Ludlow District." By 

 Miss Gertrude L. SUes, D.Sc, and Miss I. L. Slater, Newnham 

 College, Cambridge. (Communicated by Professor T. McKenny 

 Hughes, M.A., F.R.S., F.G.S.) 



After an introduction dealing with previous work in the district, 

 the authoresses adopt the following classification of the beds : — 



