208 Proceedings of Royal Society of Edinburgh. [suss; 
country rock around it. The volume remains just the same, 
whether the intruder is present or not; just as the Staffordshire 
coal miners told Jukes was the case in their district. Evidently 
the older rock has been gradually removed by some means, and 
the newer one just as gradually introduced into its place. 
Mr Clough cited some cases in which limestone had been eaten 
out when the Whin Sill was being intruded. I can corroborate 
his statements from my own observations along the Cross Fell 
Escarpment, which I mapped in connection with the Geological 
Survey of that district. Quite recently the Berwickshire Natural- 
ists’ Club paid a visit to Dunstanburgh Castle, on the coast of 
Northumberland, where the Whin Sill occurs in the upper third 
of the Yoredale Rocks. In Queen Margaret’s Cove, at that place, 
a mass of sandstone, capped by limestone, has been caught up in 
the lower part of the dolerite, and in the caught-up portion 
several protrusions of the Whin Sill into the limestone are clearly 
shown, some of which are surrounded by limestone in an un- 
broken condition, just as occurs in the sandstones and shales 
already mentioned. 
Turning for the occasion to the evidence afforded by an 
intrusive mass of dolerite from a foreign locality, it may be men- 
tioned that Mr Walcot Gibson of the Geological Survey of Great 
Britain has a photograph which shows the very uneven upper 
surface of a bed of dolerite which has been intruded into sand- 
stones. This photograph has been traced, and is reproduced in 
outline in fig. 12. It will be observed that in this instance again 
there is absolutely no evidence of the beds above the dolerite 
being lifted, or “laccolitised,” so that their dip conforms to the 
surface of the sandstone. On the contrary it is quite evident 
that one of two things has happened in this case : either the sand- 
stone has been deposited after the dolerite, or else the latter has 
eaten its way into the sandstone. As there is abundant evidence 
of contact metamorphism in the rock in the marginal zone next 
the dolerite, the alternative explanation may be at once dismissed 
from further consideration. 
Passing now to notice cases in which the basic intrusive 
mass comes into contact with coal seams, beds of oil shale, of 
blackband ironstone, or other carbonaceous rocks, it may be men- 
