HIS GEOLOGICAL RELATIONS. 129 



rate of lacustrine sediments, must have taken thousands 

 of years to accumulate ; cave-earths and stalagmitic 

 incrustations, which, considering the slow increase of 

 calcareous oozings, must also have taken long ages to 

 augment to several yards in thickness ; and river-drifts, 

 now so high above the eroding stream, and in valleys 

 so altered in their outlines, that hundreds of centuries 

 must have elapsed in the work of erosion, transporting, 

 assorting, and re-eroding, of the shiagly and gravelly 

 debris. There is no getting over these facts — no 

 calling LQ of cataclysms, no sheltering under appeals 

 to greater activity of agency in former ages. 

 Cataclysms may assist in the rapid alteration of river- 

 courses, but they cannot produce stalagmite in caves, 

 lay down finely-laminated sediments in lakes, or pro- 

 mote the growth and decay of marl-forming shell-life in 

 lacustrine waters. Greater activity of physical agency 

 may produce vaster results iu shorter periods, but no 

 activity of this sort can be applied to the usual term of 

 life — to the reproductive growth and decay of the 

 myriad generations of plants and animals imbedded in 

 these formations. But granting the physical evidences 

 were unsatisfactory, what shall be said to the remains of 

 extinct species of ox, of reindeer, musk-ox, Irish deer, 

 mammoth, rhinoceros, and other extinct animals, 

 occurring in these lake-silts, river-drifts, and cave- 

 earths, and unmistakably the contemporaries, and 



