CHAP. XXXI 
THE VENTS OF EASTERN FIFE 
89 
volcanoes. The margin of a neck or volcanic vent is thus found to he 
almost always sharply defined. The rocks through which the funnel has 
been drilled have been cut across, as if a huge auger had been sunk through 
them. This is well displayed in the beautifully perfect neck already cited 
at Newark Castle, near St. Monans 
(Fig. 224). The strata through which 
this neck rises consist of shales, sand- 
stones, thin coal and encrinal lime- 
stones, dipping in a westerly direction 
at angles ranging from 25° to GO . 
At the south end of the neck they 
are sharply truncated, as if by a fault. 
Elsewhere they are much jumbled, 
slender vein-like portions of the tuff 
being insinuated among the projecting 
strata. A large vertical bed of 
sandstone, 24 yards long by 7 yards 
broad, stands up as a sinuous reef 
on the east side of the vent (s). It 
is a portion of some of the surround- 
ing strata, but, so far as can be seen 
at the surface, is entirely surrounded 
with agglomerate. Here and there 
the shales have been excessively 
Fig. 224. — Plan of volcanic neck on beach 
near St. Monans. 
T, Neck of tuff enclosing a mass of sandstone (s), and 
piercing sandstones and shales with beds of lime- 
stone, ( 1 1), and a thin seam of coal (c) ; B, Basalt 
“white-trap” dyke. The arrows show the dip of 
the strata. 
crumpled, and at the north end have 
been invaded by a vein of basalt 
which, where it runs through them, assumes the usual clay-like character. 
The strata have been blown out, and their place has been occupied by a 
corresponding mass of volcanic agglomerate. But their remaining truncated 
edges round the margin of the orifice have undergone comparatively little 
alteration. In some places they have been hardened, but their usual 
texture and structure remain unaffected. 
In a few examples, the progress of denudation has not advanced so far 
that the cone cannot still be partially made out amidst its surrounding 
masses of tuff. One of the most interesting of these is Largo Law, of which 
an outline has been given in Fig. 209. The accompanying section (Fig. 2 20) 
represents what appears to me to be the structure of this hill. Each of the 
two now conjoined cones was probably in succession the vent of the volcano. 
The southern and rather lower eminence, as already mentioned, is traversed 
by rib-like dykes of basalt, which point towards its top, where there is a 
bed of the same rock underlying a capping of tuff. On its eastern declivity 
lies the basalt stream already described (p. 87). The higher cone is sur- 
mounted by a cake of basalt which, as I have above suggested, may have 
solidified at the bottom of the latest crater. Of course all trace of the 
crater has disappeared, but the general conical form of the volcanic mass 
remains. Houbtless, still more of the old volcano would have been removed 
