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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .Mar. 19,
Sandstone-area of Maucliliney Ayrshire. — We have now to leave
Dumfriesshire and go to near the centre of the adjoining county
Ayrshire. In this district, around Mauchline, there is another patch
of red sandstone and breccias exhibited. About a quarter of a mile
to the south of the Mauchline Station this sandstone is worked. It
possesses all the features which characterize the false-bedded sand-
stones above the breccias in the several Dumfriesshire areas, and
seems to be of considerable thickness. About half a mile further
south, at Ballochmoyle, in the course of the Water of Ayr, we have
a beautiful section exhibiting these sandstones and the strata upon
which they repose.
Immediately above the bridge over the Railway the red sandstones
dip N. 50° W., at an angle of 15° ; and as we go up the Water of
Ayr, from newer to older beds, we see a great change taking place
in the nature of the deposits.
The lowest strata of the sandstones are soft, and rest upon a thick
series of breccias, which in appearance are like those at the south
entrance of the Drumlanrig tunnel, and consist of angular fragments
of amygdaloid, in the cavities of which are nests of zeolitic minerals.
In the highest portions of these breccias there are thin beds of a
siliceous limestone, of a purplish colour, but in these I found no
organic remains. See Section, fig. 4. In going up the stream, from
Fig. 4. — Section near Ballochmoyle, Water of Ayr, Ayrshire.
c. False-bedded sandstones.
b, b. Impure limestone.
a, a. Breccia.
the higher to the lower beds of the breccia, we come upon a trap-
dike which cuts off the beds, and from which the fragments entering
into the composition of the breccias have been obtained ; and on the
eastern side of the dike we have Carboniferous grits, similar to those
which surround the sandstones of the Thornhill area.
The association of the several rocks here is intimately connected
with what is seen at the entrance of the Drumlanrig tunnel, the only