9{) 



ledged that where there are no sand or gravel beds, it is extremely 

 difficult to determine their respective horizons. Sometimes the 

 boulder clay may be slightly stratified, but usually there is not the 

 remotest appearance of stratification, the stones being mixed pell- 

 mell in the clay without the slightest order, and they are almost 

 invariably either rounded or sub-angular, and not infi-equently are 

 scored with glacial striae. The sand and gravel beds intercalated 

 with the boulder clay, occur with great fire^juency, and often with 

 considerable constancy. They are assumed by probably a large 

 majority of geologists, to occur both above and below true boulder 

 clay, and have thus been termed Middle Drifts. They are very 

 complex in their characteristics, often contain fossil remains of 

 warmer than Arctic types, and present extreme difficulties in many 

 respects. If we grant that there are two deposits of undoubted 

 boulder clay, the product in each case of the extremest cold, 

 during which the country was enveloped in an ice sheet that must 

 have stifled all life, except the most hyperboreal forms ; and that 

 these two epochs were separated by a period of milder climate of 

 sufficient duration to allow of the immigration of numerous forms 

 of life, which during the preceding glacial epoch could not have 

 existed in any near vicinity, we are compelled to grant an enormous 

 period of time, and such immense physical changes, as we are 

 only warranted in doing on the most indisputable evidence. I fear 

 that in geological matters we are too ready to assume on the 

 slightest pretext gigantic changes, that could only occur after the 

 lapse of incalculable ages ; possibly the simplest geology is the 

 best, and more extended research and greater knowledge will 

 undoubtedly tend to abolish theories which constantly require 

 cataclysms, and to substitute in their place the slow silent agencies 

 which we may see every day at work. We have some slight 

 evidence in the earlier stone-records of other glacial epochs, but we 

 have no foundation to assume that there were many of them, and 

 we should be very careful as to our evidence before we affirm that 

 there were two glacial periods, comparatively speaking, close 

 together, and in the very latest chapter of geological history. If 

 boulder clay formation could be proved to be the product of one 



