( 39 ) 
A General View of the Phenomena displayed in the neighbourhood 
of Edinburgh by the Igneous Rocks, in their relations with the 
Secondary Strata ; with reference to a more particular descrip- 
tion of the Section which has been exposed to view on the south 
side of the Castle Hill. By Major-General Lord Greenock, 
C. B. F.R.S. Ed. 
(Read 16th Dec. 1833.) 
Tue country in which Edinburgh is situated has no great 
elevation above the level of the sea, presenting a gently undu- 
lating surface, except where hills of igneous origin, in groups, or 
perfectly insulated, rise abruptly through the strata, which con- 
sist of the sandstones and shales of the coal-formation, with occa- 
sional beds of limestone, which they overlie, and this country is 
more or less covered by old and. new alluvial deposits. 
The views suggested by these hills to the penetrating genius 
of Hurzon, who may be justly considered the founder of mo- 
dern geology, first led to the knowledge of the true nature and 
origin of the trap-rocks. Their analogy to those produced by 
existing volcanoes, and the phenomena observed in their rela- 
tions with the secondary strata, leave no doubt as to their having 
been poured out from the interior of the earth in a fluid or viscid 
state, through fissures in the strata occasioned by subterranean 
convulsions—not, however, in the open air, like currents of lava 
from recent craters, but in sheets or masses at the bottom of the 
sea, their cooling and consolidation having evidently been slow 
and. gradual, under great pressure, such as might be produced by 
a large volume of superincumbent water, as was ably illus- 
