CONCLUDING OBSERVATIONS. 319 



regard to this plan is like what we see as we look upon 

 a potter as he makes some vessel. We see the general 

 plan developed very soon after he begins to turn the ball 

 of clay, and the minutiae of the plan appear more and 

 more as he proceeds. Just so the investigations of geol- 

 ogists have shown how the continents, at the very com- 

 mencement of their formation, had a shape which looked 

 toward what they now are, and how they were gradual- 

 ly developed, and at length were finished in all the mi- 

 nutiae of their diversification. And I may remark here 

 that each continent had its own plan. While, for exam- 

 ple, the Xorth American continent, as you saw in 267, 

 began with the formation of one long island, Europe was 

 at first a group of islands, which were afterward united 

 together. There was a plan, also, in regard to the ani- 

 mals of the earth. This is seen in the preservation of 

 the four grand divisions of animals from the beginning, 

 through all the changes of genera and species; in the 

 gradual advance from the lower up to the higher forms, 

 through the ages of the earth's growth ; in the introduc- 

 tion of particular forms for special purposes, at certain 

 periods, and in certain localities ; and in the final con- 

 summation of the animal kingdom, in which, after all its 

 long line of successions, there was an adaptation of it to 

 the wants of man, who was constituted its ruler. The 

 same may be substantially said of the vegetable kingdom. 

 432. Time in Geological Processes. I have here and 

 there, in previous chapters, given some illustrations of the 

 great lengths of time required for the formation which 

 make up the crust of the earth. You will recollect the 

 calculation of Liebig, noticed in 318, in regard to the 

 formation of coal. Calculations have also been made in 

 regard to the deposition of the strata of rocks, and the 

 estimates for all the formations, from the Azoic down, 

 reach a sum total of over fifty million of years. The es- 

 timates are based upon the rate at which rocks are de- 

 posited and solidified in lakes and seas at the present 



