114 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 
must have taken place prior to the invention of firearms. The 
other and much more modern portion is placed adjacent and at 
right angles to the old building. It was erected in 1627 by John 
Crawfurd of Kilbirnie, and extensively repaired about the year 
1756 by George, third Viscount Garnock (who had also succeeded 
to the Earldoms of Crawfurd and Lindsay). During the progress 
of these repairs, however, the house was accidentally set on fire 
and burned to the ground. 
On the left side of the approach to the castle a large patch of 
Senecio saracenicus was seen, measuring five feet in height, but 
not yet in flower. 
At the entrance to Pitcon Glen, the stream has cut into a thick 
bed of boulder clay for a distance of from 50 to 60 feet, but a 
considerable portion still remains to be penetrated. The bed of 
the stream contains many limestone boulders, but, as there are no 
outcrops of limestone, either here or further up the’ burn, these 
blocks must have come from a limestone outcrop situated more 
than a mile to the north. Near this spot there is a numerous 
fleet of boulders, mostly derived from the hill porphyrites, one of 
which is the largest carried block in the district. 
As the party proceeded down the glen, it was observed at one 
place that the ash beds beneath the Hourat limestone were exposed 
on the north side of the glen, the top portion of the section being 
dull red, and the bottom greyish or greenish in colour. Near this, 
in another section, the ash contains a few volcanic bombs, and, 
still further down, the stream has cut its channel through the 
Hourat limestone, forming a beautiful fantastically-sculptured 
gorge, in which the full thickness of the limestone bed—about 20 
feet—can be seen. Here, too, are many limestone caves in embryo, 
from one of which a run of very fine water issues. 
The limestone is suddenly cut off by a 27-fathom hitch, which 
brings down the clayband to this level. Near the junction of the 
Gowkhouse and Pitcon Burns, a favourable opportunity occurred 
for inspecting the clayband ironstone seam (134 inches thick), 
which is embedded between thick seams of black shale. 
After emerging from the glen, the party ascended to Swinlees 
Quarry, where the Hourat post of limestone was worked about 
fifty years ago. The rock shows a somewhat weather-beaten face, 
on which many fossils are to be seen, especially Lithodendron, 
