WITH ANTICLINAL AXES AND FAULTS. 343 



Turning now to the second case, of which we have an example 

 in the fault adjacent to the southeastern base of the Little North 

 Mountain, we at once discern this important difference, that 

 while the direction of the dip and inversion is the same as in the 

 preceding, the hig-h groimds of the Little North Mountain lie to 

 the northivest. Hence the downward drainage between the strata 

 on the flank of this ridge, conforming to the southeastern dip of 

 the rocks, must hetotvards the fcmlt, and the hydrostatic columns 

 communicating with the heights, and following the plane of dip, 

 will in many cases have sufficient power to force up the heated 

 waters to the surface, at certain points along or near this line. 



The numerous class of thermals whose point of issue is exterior 

 to the bounding ridges of an anticlinal valley, owe their origin, as 

 I conceive, to the same general agencies as have been above con- 

 sidered. Bearing in mind, that in the great majority of cases 

 they flow out from the northicestern bovindary, the vertical or in- 

 verted rocks of which are greatly shattered, and that their point 

 of exit is generally below the level of the valley, it is reasonable 

 to suppose that, in many instances, they have been conveyed 

 away from beneath the surface of the valley, when, in a less fis- 

 sured condition of the strata towards the northwest, they would 

 have been forced to rise at some point within its confines. In 

 many cases, too, the downward drainage of the northwestern 

 ridge itself is fully adequate to carry the requisite amount of 

 fluid to the seat of heating and chemical action, and, by hydro- 

 static power, to raise it again to the surface at a much lower 

 level. 



In speculating with regard to those thermals which issue at 

 or near the base of a continuous anticlinal mountain, it is im- 

 portant to bear in mind, that while cracks and partings are found 

 generally attendant upon flexures of the strata, these openings 

 are by far the most numerous' and extensive in that part of the 

 curve where the change of direction is most abrupt. Hence 

 they will be found descending in the interior of the mountain, 

 much in the direction of the axis-plane, and will lie nearer to the 

 northwestern than the southeastern side. The meteoric waters 

 supplied through these channels, will find an exit either by the 



