IV 



BULLETIN OF THE NATURAL HISTORY SOCIETY. 



Switzerland, the Canadian Rookies, | 

 r.nd in other localities. In fact, 

 wherever glaciers exist, sume such de- 

 pcsits must be made to a greater or 

 less extent. The moraines of the Swiss 

 glaciers being the modern equivalent 

 of the ancient ice deposits. 



Undoubtedly England, at the time 

 of the Glacial Period, was united to 

 Scandinavia, and probably to Ireland 

 also. One immense glacier moved 

 southward, being fed by ice-streams 

 branching 5ut, both east and west, in 

 the manner of river tributaries. You 

 may ask "How is this proved ?" 



Why, by the contents of the clay. 

 The Bedfordshire Drift Clay is un- 

 doubtedly obtained in a grpat mea- 

 sure from the Liassic and Oolitic 

 Argillaceous deposits, which lis com- 

 paratively near at hand. In fact, both 

 are found in various locaU'ies not f^r 

 distant, the Oxford Clay lying in the 

 immediate neighborhood to the north 

 and north-east. These facts are im- 

 portant, as the number of fossils found 

 in this particular drift, which are 

 characteristic of either the Oolitic or 

 Liassic clays, show that the bu'k o!" 

 the material must have been obtained 

 ficm these sources. 



Those fossils and rocks derived from 

 material lying at a greater distance, 

 are naturally much fewer in number, 

 although some must have been brought 

 a long way, as for example the Trig- 

 onia Pulchella, whilst some of the 

 rock fragments would seem to be of 

 Scandinavian origin. 



There has been much speculation r.s 

 to the chronology of the Glacial Period. 

 Sir Charles Lyell and his disciples 

 gave a practically unlimited ilme to 

 life, as we know it in geologv. 



More modern geologists, guided in a 

 great measure by astronomers and 

 physicists, have arrived at conclusions 

 strikingly different from those of the 

 older school of writers. Here is the 

 contrast, if figures of such magnitude 

 can be sufficiently grasped to appre- 

 ciate their import. 



500.000,000 years ago the Eozoon 

 would be flourishing, according to Sir 



Charles Lyell. Of course, it is very 

 possible that you do not accept the 

 evidence as sufficient to show that 

 any organism existed, prior to the 

 reigr of the Triiobites. Anyway, that 

 is the age given when the Laurentian 

 rocks were being formed. 



Young and Wallace, two more mo- 

 dem mathematical geologists, give 

 about 30,000,000 years only, as the time 

 of the "Dawn of Life." 



Dana, in his geology, gives this pro- 

 portional ratio : Palaeozoic, 22; Mes- 

 ozoic, 6; Tertiary, (together with the 

 Post-Tertiary) 2. From this you will 

 gather that the whole of the deposits 

 ranging from the Lower Eocene to the 

 Pliocene, onward through the Pleisto- 

 cene to the present time, is only 1-15 

 of the geological life period. Some 

 authorities give a much less propor- 

 tionate time value than this even, for 

 the Kainozoic Age. Out of this time, 

 only a small portion can be taken for 

 the Glacial Period, occurring, as it 

 does, after all the great deposits of 

 the Tertiary Age were laid down. 

 Prestwich gives about 25,000 years, as 

 the time for the existence of the Age 

 of Ice. 



Next arises the question: How much 

 time has elapsed since the close of the 

 Glacial Epoch? From cumulative evi- 

 dence a fairly near date can be at- 

 tained. 



The Niagara Falls form, perhaps, 

 the best geological clock in existence, 

 for the purpose of giving the approxi- 

 mate date when this period ended. It 

 took years to work out a satisfactory 

 result, and such men as Sir Charles 

 Lyell, Jame5 Hall, and Woodward all 

 aided in solving the problem. It is 

 a. very well authenticated fact that 

 the river Niagara is of post-glacial 

 date, as is also Lake Erie, and a large 

 number of Ihe Canadian lakes. Lake 

 Ontario was probably pre-glacial, the 

 Grand River and its tributaries being 

 the means by which the whole of the 

 valley which is now Lake Erie was 

 drained. This river course was com- 

 pletely diverted by ice-action, as be- 



