560 THE JOURNAL OF GEOLOGY. 



to the seaward as in the Appalachian. The erosion of the Cre- 

 taceous and Tertiary times probably cut down the Sierra to very 

 moderate proportions and reduced it to an almost senile condi- 

 tion. At the end of the Tertiary a gr?at fault and bodily uplift 

 of the whole Sierra block on its east side transferred its crest to 

 the extreme eastern margin, greatly increasing its height and 

 rejuvenating its erosive vigor. 



3. Coast Range. — The formation of the Sierra transferred the 

 coast line westward of that range and the present place of Coast 

 Range became marginal sea-bottom, receiving sediment from a 

 now greatly increased land-mass. This continued until the end 

 of the Miocene when the Coast Range was similarly formed. 



We might multiply examples, but these are deemed sufficient 

 to illustrate the principles. 



MINOR PHENOMENA. 



We have given only the most fundamental phenomena, i.e., 

 those which reveal the mode of origin, and upon which, there- 

 fore, a true theory must be founded. But all other minor phe- 

 nomena associated with mountains are well explained by the view 

 above presented and their explanation confirms the view. For 

 example : 



I. Eruptive Phenomena. — We have seen that beneath a moun- 

 tain, before and at the time of its formation, there is a deep-seated 

 core of liquid or semiliquid matter. Also it is evident that the 

 strong foldings of the strata in the act of mountain formation 

 must produce fissures parallel to the folds and to the mountain 

 axis, and that these fissures may reach down to the submountain 

 liquid matter. In the act of mountain formation, therefore, the 

 submountain liquid must be squeezed into the fissures forming 

 dikes, or through the fissures and poured out on the surface as 

 great lava floods, covering sometimes thousands of square miles. 

 In most cases subsequent erosion has swept these overflows clean 

 away leaving only their roots as intersecting dikes. Only the 

 most recent still remain. On these great fissure-eruption lava- 

 fields, ordinary volcanic or crater eruptions continue for ages 



