IV 



Huttori s Doctrines 169 



expanse of water in which they could have been de- 

 posited. 



Thus the first conclusion established by the Scottish 

 philosopher was that the greater part of the land con- 

 sisted of compacted sediment which had been worn away 

 from some pre-existing continent, and had been spread 

 out in strata over the bed of the sea. He realized that 

 the rocks thus formed were not all of the same age, but, 

 on the contrary, bore witness to a succession of revolu- 

 tions. He acknowledged the existence of a series of 

 ancient rocks which he called Primary, not that he believed 

 them to be the original or first-formed rocks in the struc- 

 ture of the planet, but that they were the oldest that had 

 then been discovered. They included the various schists 

 and slates which Werner claimed as chemical precipitates, 

 but in which Hutton could only see the hardened and 

 altered mechanical sediments of a former ocean. Above 

 them, and partly formed out of them, came the Secondary 

 strata that constitute the greater part of the land. 



But all these sedimentary deposits have passed from 

 their original soft condition into that of solid stone. 

 Hutton attributed this change to the action of subterranean 

 heat. In his day the chemistry of geology was exceed- 

 ingly imperfect. The solubility of silica, for instance, and 

 its capacity for being introduced in solution into the 

 minutest crevices and pores of a rock were not known. 

 It need not, therefore, surprise us to find that in the 

 Huttonian conception the flints in chalk were injected 

 into the rock in a molten state, and that the agate of fossil 

 wood bore marks of igneous fusion. Hutton did not realize 

 to what an extent mere compression could solidify the 



