87 



Leda clays afibrd good substance for modelling purposes and they have 

 already been used to a certain extent in this direction. 



There is a large percentage of alumina in these clay deposits, 

 and when we think of the vast advantages which the metal alumi- 

 niuvi presents over such substances as iron, copper, lead and zinc, it 

 may not be amiss to look forward to the time when a process shall 

 be discovered which will enable its being manufactured from clays 

 such as we have at our very doors. Nay, if I am rightly informed, a 

 series of very successful experiments have been carried on by French 

 chemists and others of late by means of which that metal can be pro- 

 duced, but at a cost which, at the present time, is too great so that this 

 aluminium industry cannot compete with that of iron. Those who 

 are familiar with the properties of this metal will clearly see what 

 advantages the community would reap if a aluminium could be manu- 

 factured cheaply and from the clays which are so abundantly 

 distributed with us. 



i\ ncl to sum up the results thus obtained in the examination of 

 the Post-Tertiary deposits of Ottawa and vicinity, an ideal vertical sec 

 tion, made to include the various measures which compose them is 

 here given : It is based on an actual section taken in the excavations 

 along Waller street, not far from Eideau street and is supplemented 

 by data obtained from other quarters. The lowest measures are those 

 which belong to the " Boulder or Glacial Clay " or '* till " formation 

 and are seen to rest on the Cambro-Silurian formations of the district 

 unconformably. Their thickness is considerable in numerous places 

 but varies materially, according to the district in which they occur. The 

 *' Leda Clay " formation overlies this glacial deposit and contains fossils 

 of various kinds entombed in strata. The thickness of this marine 

 deposit is considerable in some places whilst it has been completely 

 eroded or denuded in others at a remote, but subsequent period to its 

 deposition. The clays often carry erratics with them. Then comes a 

 vseries of stratified gravels or coarse sands in which many large angular 

 and partially rounded boulders occur overlying the Leda Clays, in 

 most cases apparently conformably, but oftimes, no doubt, unconform- 

 ably as the line of contact is very sinuous and points to a good portion 

 of the clay as having been carried awny. Overlying these gravels are 



