Gethie— Old Volcanic Action at Burntisland. 25 
that in the upper fireclay a large angular stone is stuck 
in a vertical portion. With this single exception there were 
no stones of any kind observed in the bed, which continued 
throughout a fine-grained fireclay. The intruded block was 
of a pale felspathic greenstone, different from any of the beds 
of the cliff, and weighed perhaps six or eight pounds. It rested 
on the surface of the coal-seam, or at least was separated from 
it by an extremely thin layer of the clay. The part of the 
coal-seam immediately below it was considerably compressed, 
but did not appear to be otherwise altered in texture. More- 
over the lamine of the fire-clay, for perhaps a couple of inches 
from the bottom, were bent sharply downward along the sides 
of the stone, in the manner shewn in the figure, while a little 
higher in the bed, instead of being turned down, they rose 
slightly upward, and seemed to be heaped up around and over 
the stone. The layers above the stone shewed no trace of dis- 
turbance. Now it is plain that this greenstone block is some- 
thing abnormal and extraneous in the fireclay, and not a part 
of the ordinary sediment of that deposit. It is clear also that 
the block must have been mtroduced into the clay when the 
latter was soft and yielding, and even before the underlying 
coal-seam had hardened into stone. Indeed the time of its in- 
troduction is exactly fixed by the evidence from the stratifica- 
tion of the fireclay. The block must have come into its present 
position after the deposition of that portion of the fireclay 
which it squeezes down, and before the accumulation of the 
part which is heaped up over it; in other words, just when the 
bed of fireclay was about half-formed. It is further evident 
that as no other stones are visible, and no change takes place 
in the nature of the sediment composing the fireclay bed, the 
introduction of this greenstone block cannot have been brought 
about by the agency of currents of water. On the contrary, 
from the vertical position of the stone, the compression of the 
coal-seam, and the sharp depression of the layers of fireclay, 
we cannot but infer that the stone must have dropt upon the 
muddy bottom, and from some considerable height, to enable it 
to squeeze its way so markedly down through the clay upon 
the underlying coal. Had such a solitary block occurred in 
the heart of a deposit lke the Carboniferous Limestone of 
Treland, or the Chalk of Surrey,* its introduction might have 
* See Jukes’ Manual of Geology, 2nd edit. p. 146, for an account of blocks of 
granite, schist, and other rocks, in the Carboniferous Limestone of Dublin ; also 
a paper by R. Godwin-Austen, F'.R.S., F.G.S., ‘On a Granite Boulder found in the 
White Chalk near Croydon,’ in Journ. Geol. Soc., vol. xiv. p. 252. 
