1903-4.] Mr J. G. Goodchild on Intrusive Rocks. 
207 
on fig. 9. In this, as in the other cases cited, it is perfectly evident 
that the intrusive inass has not added its volume to that of the 
Fig. 9. — Eastern face of Dodhead Quarry, within the Golf Links, 
Burntisland, Fife. 
The sedimentary rocks here are mostly sandstones and shales, more 
or less carbonaceous in character They belong to some part of 
either the Oil Shale Series or to the subdivision of the Lower 
Carboniferous Rocks yet below that. In the lower part of the quarry 
occurs a thin band of a more calcareous type, which might be regarded 
as a finely-laminated shaly limestone. It is shown in the section by 
vertical ruling. Two or three sills of basic rock have been intruded 
into the sedimentary rocks hereabouts, and one of these, altered by 
the carbonaceous matter into “White Trap,” traverses the quarry 
from the present section northwards, maintaining throughout nearly 
the same thickness, and keeping to nearly one horizon. In Dodhead 
Quarry the “trap” begins to thicken, thin, die out, and reappear, in 
a very irregular manner, as shown by the figure, which has been 
carefully drawn in the quarry from a series of photographs taken with 
the express object of showing the phenomena in every possible aspect, 
and checked on the ground by actual measurement. 
It will be noticed that the distance between the limestone and the base 
of the sandstone remains the same at either end of the section, alike 
where the trap is present and where it is wanting. The evidence of 
replacement of the country rock by the “ trap’’ is quite clear. There is 
also quite clear evidence of local displacement below the trap. This 
phenomenon sometimes occurs in the cases in which there are two sills 
present (as there are in the present case, the second occurring a little below). 
It is presumed that the forcible injection of the magma forming the 
sill displaced part of the magma forming the dyke-like extension of tlfe 
mass and ruptured the sediments in the manner shown. The patch 
marked B is separately represented in fig. 10. 
The section embodies examples of nearly all of the phenomena which 
usually accompany the intrusion of eruptive masses, and hence it has 
been selected as a typical section. 
