66 T?iE Ottawa Naturalist. 



diving headlong into the foaming current till they reached some 

 embayment or eddy. 



The botanists, as usual, were in the majority and their 

 efforts were amply rewarded with a splendid harvest of beauti- 

 ful plants. 



On reassembling at the rendez-vous the President, Mr. F. T. 

 Shutt, addressed the members present and in well-chosen and 

 happy remarks referred to the success of each department of the 

 Club represented. He then called upon the different leaders 

 present to describe some of the specimens collected and note 

 objects of interest observed. 



Dr. H. M. Ami, being called upon as geologist, gave a 

 brief sketch of the history of the district from a geological stand- 

 point. Chelsea was situated just where the two extremes in 

 geology meet, viz., where the Archaean or oldest formation rests 

 up on the Pleistocene or youngest series of rocks. 



The Archaean rocks of the district were very extensively 

 and beautifully developed from Chelsea northward to Hudson 

 Bay, and the Gatineau River which flowed at our feet so tortu- 

 ously and rapidly was one of the oldest streams in Canada— the 

 bed being cut out of the hard gneissoid and granitic rocks of the 

 Archaean system of which the Laurentian is the basal or funda- 

 mental formation. 



In the newest, or Pleistocene deposits, were to be found : 

 I. Boulder-clays and " till " of glacial origin. These were 

 remnants of the "Great Ice Age" which has left markings 

 all over the Laurentide Hills and on the softer and newer Ordo- 

 vician limestone strata of Parliament Hill and Ottawa generally. 

 n. Marine clays of the " Leda clay" formation capped by 

 marine sands and gravels, both of which carried sand. From 

 specimens collected by Messrs. W. J. Wilson, D. B. Dowling and 

 the writer in the cutting half-a-mile north of Chelsea station the 

 following species of marine shells were obtained : — 



1. Leda (Portlandia) arctica, Gray. 



2. Macovia fragilis, Fabricius. 



