394 NATURAL HISTORY. 



fusion, enveloped its interior portion ; but this condition 

 was not to continue. All at once and it is presumed 

 it was but the work of a moment at the command of the 

 Creative Power, the scene was changed. The mighty 

 elements began to operate, producing the great upheaval 

 of the internal igneous masses, pressed upwards upon the 

 sedimentary and stratified formations already existing, 

 forced them out of their original beds or from their ordi- 

 nary position, as may be plainly discovered by examining 

 the strata exposed by excavation. A very simple illus- 

 tration may give the reader an idea of such an upheaval, 

 if he will imagine the leaves of a book lying superposed 

 in a horizontal position, and pressed upwards with irre- 

 sistible force by some powerful agent below how each 

 separate leaf will be dislodged, twisted, and wrested from 

 its original position, and at last torn asunder by the pro- 

 truding force acting baneath them, in the successful effort 

 for freedom. The escaping mass forms the granite or 

 massive rocks seen in the primary rock formation, which 

 term includes all the loose materials soils, clays, gravels 

 substances which were previously in a state of fusion. 



How those upheavals have originated is hard to tell. 

 Perhaps the most plausible explanation is the following : 

 The earth, which, as is well known to all, turns upon its 

 own axis, before the time of the first upheaval performed 

 its rotatory motion more rapidly than at the present ; that 

 suddenly the rate of its diurnal revolution was reduced 

 to its present measure, therefore, if this theory is true, 

 it may be supposed that those heavy masses of stone or 

 mineral materials, either wholly or partially in a state of 

 fusion, which we now call primitive rock (granite, which 

 seems to form the foundation stone of the great geological 

 edifice) might be able, by the indwelling centrifugal force 



