Prof. OC. Lapworth—Ballantrae Rocks of South Scotland. 21 
complex formed of—(a) the Stinchar limestone and conglomerate 
series; (b) a stratiform series of sedimentary and volcanic rocks 
of much earlier date ; and (c) intruded igneous masses of subsequent 
but unknown geological age. When the first and last of these 
sections had been satisfactorily eliminated, I believed that the 
remainder—or Ballantrae series proper—would prove to be of 
higher antiquity than any of the fossiliferous strata hitherto 
recognized in the Southern Uplands.? 
In my paper? upon the Girvan succession the rocks of the Ballan- 
trae complex are thus referred to:—‘‘ These Girvan rocks (Llandeilo- 
Bala to Wenlock) appear to repose at their base upon the generally 
older igneous and altered rocks of Ballantrae. The Ballantrae rocks 
have as yet been too imperfectly studied to allow us to hazard any 
conclusion respecting their true geological age. That many of the 
rocks grouped together under this title are of far greater antiquity 
than the basement beds of the Girvan succession may be regarded 
as established by the fact that fragments of the Ballantrae rocks 
occur in the Kirkland or Purple conglomerate at the base of the 
Girvan succession. These (their) Pre-Girvan traps and ashes must 
either represent the Arenig and Llandeilo (Lower) volcanic rocks of 
Wales and Cumberland, or must be of more ancient date. On the 
other hand, rocks which are unquestionably of true Girvan age occur 
at many localities within the typical Ballantrae region itself, while 
the patches of altered or so-called Ballantrae rocks (of that memoir) 
found outside that area, as at Shallock Hill, Laggan Hill, and else- 
where, almost certainly include some greatly altered Girvan rocks.” 
The time at my disposal for working out the main object of my 
Girvan paper—namely, the determination of the natural order of 
succession among the fossiliferous rocks of the Girvan district—did 
not admit of my devoting more attention to the rocks of the Ballan- 
trae complex than was sufficient to establish their inferiority as a 
whole to the fossiliferous Girvan series. Hence all the rocks (sedi- 
mentary, igneous, and altered alike), whose position and characters 
showed that they formed a part of the heterogeneous Ballantrae com- 
plex, were provisionally grouped in that paper under the title of 
“ Ballantrae rocks.” It was perfectly clear however that before the 
Girvan stratigraphy should be regarded as even fairly complete it 
would be absolutely necessary to—(1) study in greater detail the 
rocks of the altered or so-called “ Ballantrae patches” within the 
limits of the Girvan area, and separate off their included post-Girvan 
igneous intrusions and the Girvan rocks these had hardened and 
altered, from the truly older stratiform rocks of pre-Girvan date ; 
and (2), to establish on the same paleontological evidences as those 
relied upon in determining the systematic position of the various 
members of the Girvan succession, the pre-Girvan age of those 
members of the Ballantrae complex which were held by myself to 
be of higher antiquity than the basement beds of the (Upper 
Llandeilo) Girvan succession. 
1 Compare Lapworth, Q.J.G.S. 1878, p. 341; zdid. 1882, p. 663; and Trans. 
Geol. Soc. Glasgow, 1878, p. 83. 
2 Lapworth, Q.J.G.S. 1882, vol. xxxviii. p. 663. 
