D. Balsillie — The Geology of Kinkell Ness. 501 



almost vertically in the seaward extension of the agglomerate are 

 several large masses of coral-bearing limestone whose parent stratum 

 must have measured at least 10 feet in thickness. These almost 

 certainly belong to the base of the Carboniferous Limestone Series. 



Throughout the greater part of the vent the infilling materials 

 show an obvious assortment. Standing about 10 yards to the east 

 of the middle of the three conspicuously protruding masses on the 

 beach a concentric disposition of the outcrops of the tuff layers will 

 be visible (Plate XIII). The concentricity is, however, not perfect, 

 the imperfection occurring towards the north, where the outcrops, 

 instead of swinging round to complete their respective circles, are 

 prolonged in that direction and become apparently considerably 

 displaced. Additional reference to this fact will be made further on. 



The tuff layers are often irregular and show false bedding and 

 occasional unconformity, the latter probably pointing to prolonged 

 intervals of quiescence in the history of the vent. Layers of fine 

 ash alternate with zones of coarser material and frequently preserve 

 by their indentation under a large block or bomb an interesting 

 record of some old aerial journey that was terminated by descent 

 into the soft accumulations along the inner slopes of the cone. 



The materials of the vent have apparently suffered a good deal of 

 faulting and displacement. Sometimes also they are traversed by 

 veins of dark-bedded ash that transgress the stratification proper of 

 the neck. Of these the writer has arrived at no completely satisfactory 

 explanation. Atone part there is a coarse grit containing abundant 

 blue opaline quartzes, a number of lava fragments, and at least one 

 large block of white limestone. The mode of occurrence of this 

 mass would suggest that it was laid down in some old crater pool 

 during a period of quiescence, and that the materials from which it 

 was built up were derived from some coarse, easily disintegrable grit, 

 while down the adjacent ash-slopes there rolled into the water an 

 occasional lava fragment or other block of non- volcanic origin. 



While, as Sir A. Geikie mentions, 1 " there is no evidence that lava 

 was ever discharged from this vent, the ascent of molten rock in the 

 chimney of the volcano is impressively shown by the numerous 

 intrusions of olivine basalt and limburgite that intersect the tuff." 

 These, as further pointed out by the same authority, are not all of 

 one date, but belong at least to two and perhaps three different 

 epochs of injection. The older basalt is generally a dark- green 

 decomposing felspathic olivine-hearing rock that in the majority of 

 cases has involved so many included fragments in its substance that 

 its simulation of an agglomerate is complete. The only possible 

 mode of origin of such curious and thoroughly deceptive material 

 would appear to be that the basalt had risen in the chimney in 

 a highly liquid condition, and that having caught up a large amount 

 of extraneous material early in its ascent had inserted itself among 

 the ash of the higher parts of the neck, not as a homogeneous 

 medium but rather as a species of mobile "concrete" (if it is 

 permissible to apply such a term to a natural product). On cooling 



1 The Geology of Eastern Fife, p. 210. 



