D. Balsillie — The Geology of Kinkell Ness. 505 



Limestone times and that possibly this vent ought to be relegated to 

 that period. Notwithstanding the significance which must be 

 attached to this kind of evidence, however, it seems exceedingly- 

 hard to question the validity of the contention that, in cases where 

 the stratified rocks have been folded and faulted anterior to their 

 disruption by active volcanic forces, deposition must have been 

 followed by diastropic change more closely than by igneous action. 

 Now, as "is well known, the period of comparatively stable 

 equilibrium that obtained over Western Europe during the 

 Carboniferous Period was brought to an end at the close of 

 "Westphaliau times by a powerful series of earth movements, the 

 direction of maximum stress over the Northern British area being 

 approximately from east to west. It would appear to have been at 

 this time that the folding and thrusting of the Scottish Carboniferous 

 rocks was inaugurated and carried to completion. "We may be sure 

 that such a major readjustment of internal forces as then took place 

 would not be unaccompanied, as integral in the sequence of events, 

 by its concomitant or subsequent cycle of igneous activity, and it is 

 to this period of terrestrial instability, as it affected our own country 

 in the northern part of its extent, that probably should be relegated 

 the necks of East Eife. Such a relegation — which is really only 

 bringing the vents a little nearer the Carboniferous Period than has 

 been done by Sir Archibald Geikie — in close association with a great 

 series of crustal disturbances would explain how it is that we find 

 among the igneous phenomena of the'Carboniferous rocks in Central 

 Scotland so much apparently conflicting evidence, e.g. vents later 

 than dolerite sills, east and west dolerite dykes later than vents, 

 dykes rising along faults or being shifted by them, etc. 



Referring particularly to the Rock and Spindle, there is no clear 

 evidence that this vent is necessarily later than the tilting of the 

 strata through which it rises. If the fossil fish-teeth which, as 

 mentioned, have been found to occur in the Spindle should prove not 

 to have been derived, but have been caught up directly by the 

 ascending basalt, from the floor of some old crater pool to which the 

 sea had access, they may yet be expected to afford an important clue 

 as to the age of the neck. There is one other matter also in the case 

 of this vent which may possibly suggest a somewhat earlier age. 

 Reference has been made to the concentric bedding of the ash and 

 to the fact that the outcrops of successive layers did not form perfect 

 circles. It will be clear that if the chimney were rising vertically 

 through already tilted strata the circularity of the outcrops ought to 

 be perfect, they being the traces of a series of conical shells with 

 vertical axes upon a horizontal plane. On the other hand, should 

 the chimney be tilted along with its surrounding sediments, then one 

 might expect that the outcrops should be elliptical, the degree of 

 ellipticity being an expression of the inclination of the pipe to the 

 vertical. It is perhaps some explanation of this kind that accounts 

 for the irregularity discernible in the ash at Kinkell, though it may 

 readily be argued that it is altogether unwise to reason in such 

 fashion about the deposits of an old -volcano that obviously have 

 suffered considerable disturbance subsequent to their accumulation. 



