20 : Prof. C. Lapworth—Ballantrae Rocks of South Scotland. 
anything new with respect to the conditions of rock-transformation. 
They express usefully theories as to the distribution of mechanical 
stress and its induced metamorphism, but do not give rise to any 
new kind of metamorphic processes. 
IV.—On toe BaitantraE Rocks or Sourn ScornanD AND THEIR 
PLACE IN THE UPLAND SEQUENCE. 
By Pror. Cuartes Lapwortu, LLD., F.R.S., F.G.S. 
Part I.—The Ballantrae Rocks. 
N the extreme north-west flank of the Lower Paleozoic region of 
the Southern Uplands of Scotland there occurs a remarkable 
coastal area of stratified, igneous and altered rocks, known to 
geologists as the ‘‘ Ballantrae Rocks,” from the little fishing town of 
Ballantrae, which is built upon them. They range along the shores 
of the Firth of Clyde for a distance of about 12 miles, and are well 
displayed in section in a series of rugged cliffs cut through by the 
picturesque coast road between Ballantrae and Girvan. The area 
they occupy nowhere exceeds five miles in width, and is limited 
inland by the smoother regions floored by the barren greywackés of 
the Uplands and the fossiliferous strata of the Girvan district, but 
this inland boundary is everywhere curiously broken and irregular. 
The rocks occurring within the limits of the Ballantrae district 
consist of—(a) conglomerates, limestones, shales, quartzose flag- 
stones, and volcanic grits and tuffs; (6) broad sheets of serpentine, 
porphyrite, and various crystalline rocks; and (c) irregular masses 
of gabbro, diabase, and dolerite. Of the mutual relationships and 
true systematic position of these rocks, very diverse views have 
been advocated by geologists. Some of the unaltered limestones 
within the Ballantrae area were proved by Mr. Carrick Moore,! as 
early as 1848, to contain the same fossils as the well-known lime- 
stones of the Stinchar valley (and consequently to be of Llandeilo- 
Bala age). Since that date a few additional fossils have been recorded 
from the rocks of the area,’ but these have all been procured from 
the same well-marked limestone zone. 
The presence of these Llandeilo-Bala fossils in the limestones 
of the Ballantrae district has been very naturally held by most 
geologists as fixing generally the geological date of the associated 
stratified, igneous, and altered rocks. By some this deduction has 
been carried out fully, and the whole of the Ballantrae rocks have 
been described as Bala beds in various stages of metamorphism.® 
By others, however, while the Ballantrae rocks were placed, as a 
whole, with the Stinchar Limestones at the base of the fossiliferous 
Girvan sequence, some of their crystalline members were regarded 
as of igneous and eruptive origin.* Finally, others, who were aware 
of the faulted and convoluted character of the region, have suggested 
that some of its included rocks may be even of Pre-Cambrian age.° 
By myself the Ballantrae rocks have been looked upon as a 
1 Q.J.GS. 1849, vol. v. pp. 7-17. * Explan. Geol. Sury. Scot. Sheet vii., p. 9. 
3 J. Geikie, Q.J. 'G.S. 1866, vol. xxii. p. 5138-534. 
a Murchison, Siluria. 5th ed. p- 145, note. 
5 Hicks, Q.J.G.S. 1882, vol. viii, p- 665. 
