66 APHORISMS AND REFLECTIONS 



false image of what has been the result of our 

 subjecting: it to a jet of fervent, though nowise 

 brilliant, thought to-night. It has become luminous, 

 and its clear rays, penetrating the abyss of the 

 remote past, have brought within our ken some 

 stages of the evolution of the earth. And in the 

 shifting "without haste, but without rest" of the 

 land and sea, as in the endless variation of the forms 

 assumed by living beings, we have observed nothing 

 but the natural product of the forces originally 

 possessed by the substance of the universe. 



In certain parts of the sea bottom in the immediate 

 vicinity of the British Islands, as in the Clyde 

 district, among the Hebrides, in the Moray Firth, 

 and in the German Ocean, there are depressed areae, 

 forming a kind of submarine valleys, the centres of 

 which are from 80 to 100 fathoms, or more, deep. 

 These depressions are inhabited by assemblages of 

 marine animals, which differ from those found over 

 the adjacent and shallower region, and resemble 

 those which are met with much farther north, on the 

 Norwegian coast. Forbes called these Scandinavian 

 detachments " Northern outliers." 



How did these isolated patches of a northern 

 population get into these deep places ? To explain 

 the mystery, Forbes called to mind the fact that, in 

 the epoch which immediately preceded the present, 

 the climate was much colder (whence the name of 

 " glacial epoch " applied to it) ; and that the shells 

 which are found fossil, or sub-fossil, in deposits of 

 that age are precisely such as are now to be met 

 with only in the Scandinavian, or still more Arctic, 

 regions. Undoubtedly, during the glacial epoch, 

 the general population of our seas had, universally, 

 the northern aspect which is now presented only 



