154 TRANSACTIONS—PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
the cause may be for their exclusiveness, the fact remains that they 
confine themselves solely to one locality in our Islands; stray vagrants 
have been occasionally observed and recorded in other parts of the 
country, but the true home of the British Crested Titmouse is in the 
old primeval forest district on Speyside, with its murmuring pines and 
rippling streams, where the air of the mountains is scented with 
sweetgale, and with the resinous odour of fir branches. In this 
secluded region, well suited to their reserved habits, they find plenty 
of food all the year round, and, possessing constitutions capable of 
resisting any changes of temperature likely to occur in Scotland, 
they are independent of the causes which influence the migration of 
birds in general. 
XVL —On a Banded Hornblende Schist at Balhoulan Quarry^ 
Pitlochry, 
By Henry Coates, F.R.S.E., and Peter Macnair. 
(Read 14th January, 1897.) 
Amongst all the sections of hornblende schist we have examined 
in the southern Grampians, that in Balhoulan Quarry, near Pitlochry, 
is one of the most interesting. The quarry is situated about half-a- 
mile north-west of the village, to the east of the Highland Railway, 
and has evidently been worked for a considerable period, as some of 
the faces are old and weathered, while others are quite fresh, showing 
evidence of more recent working. The stone is principally used for 
macadamising the roads. 
The study of these hornblende schists, or sheared basic rocks, 
has engaged considerable attention ever since the publication of Mr. 
Harris Teall’s paper on the Scourie Dyke.* That an originally crys¬ 
talline igneous rock may be made to assume the appearance of a 
foliated or schistose structure is now placed beyond dispute. It is to 
another set of phenomena presented by these sheared basic rocks we 
now revert, believing that the sections at Balhoulan Quarry present 
some tangible data for the solution of some of the problems connected 
therewith. We refer to the peculiarly banded structure presented by 
so many of these hornblende schists, this structure being particularly 
well seen in Balhoulan Quarry. We had previously on several 
occasions noted a banded structure amongst the hornblende schists 
of Loch Tay and Killin. Usually they presented a finely banded 
appearance, the bands varying from a mere line to a quarter of an 
Quart, Jotir. Geol. Soc., Vol. XLL, p. 133 (1885). 
