10 ON CHANGES IN THE DISPOSITION 



vial course to a stream, once carried that over its rocky 

 bottom ; as that bottom, successively lowered, can often 

 be traced on the declivities of the hills, displaying 

 those marks of wear which have so often been idly 

 attributed to diluvian currents. 



Such is all the analysis I can here afford of this par- 

 ticular branch of a subject which might well occupy 

 a volume ; but I must here notice one or two of the 

 main consequences of this destructive power. Such 

 are the changes of place to which rivers are subject ; 

 too often neglected or misapprehended. Among these, 

 the change of the course of the St. Lawrence near 

 Quebec is one of the most noted. In this way also, 

 the Soane, which once joined the Ganges at Patna, is 

 now many miles distant from it at that place ; while 

 the Cosa once met it almost fifty miles lower than it 

 does now. Thus too did Lahore lose its commerce 

 by the alterations of the Ravee. If the Burhampooter 

 is noted for the changes of its channel, the same is 

 true of the Wolga and of many other rivers : while, 

 in our own country, under other changes, the Almond, 

 once entering the sea above Perth, now flows into the 

 Tay, while the Earn joins it at that almost neutral 

 point which shows, at once, what it was and what it 

 is destined to be. Of mere changes of level and place 

 within the same valley, the examples are endless. If 

 Saussurehas noted the course of the Rhine on the side of 

 Mont Saleve, I have already pointed out a similar case 

 in the Tay, while such examples can be traced every- 

 where. In plains, these changes are far more compli- 

 cated and extensive ; while the reason must now be 

 'obvious, in the nature of the materials of the bed, and 

 of the declivities : and thus a great river in a great 

 plain wanders over miles in the course of centuries, 

 while thus also does it either multiply its channels or 

 the reverse. All geography furnishes endless exam- 



