62 Prof. C. Lapworth—Ballantrae Rocks of South Scotland. 
tural lines, to which their axial planes strike more or less parallel, 
along which they are practically perpendicular, and from which, or 
to which, they slope as we pass outwards in opposite direetions. 
These neutral lines run longitudinally (but somewhat obliquely) 
through the Upland region from sea to sea. The southern line 
sweeps from St. Abb’s Head past Hawick and Dumfries towards the 
Mull of Galloway, and the northern line from Dunbar through the 
Lammermuir and Moorfoot Hills, past Lead Hills and Carsphairn to 
the sea near Port Patrick. From the opposite sides of the Southern 
(Hawick line) the axial planes of the parallel overfolds slope out- 
wards to the south-east and north-west, the axes of the two opposed 
sets of folds having been pushed over in opposite directions upon the 
neutral line. Along the opposite sides of the northern (Lead Hills) 
line the axes of the inverted folds usually dip inwards, the axial planes 
of the two opposed sets of folds sloping obliquely outwards above from 
off the neutral line. In this second case (Lead Hills line) we have 
clearly nothing more than the ordinary “fan structure ” of mountain 
areas. In the first case (Hawick line) we have merely the “fan struc- 
ture”? inverted. I have discussed elsewhere! the stratigraphic 
significance of these forms in mountain areas generally, and have 
shown that we must naturally expect to find the deepest strata in 
the ‘“‘fan structure” (endocline) or pseudo-synclinal form and the 
highest in the folds of the inverted fan structure (exoelne) or 
pseudo-anticlinal. These deductions are strikingly exemplified in 
the present instance. The whole of the Gala terrane has been swept 
off-for some miles on both margins of the Lead Hills pseudo-syn- 
clinal, and the locally thick Moffat terrane, which is there some 
thousands of feet in vertical extent, has been eroded almost to its 
base. Along the Hawick pseudo-anticlinal, on the contrary, the 
rocks of the Moffat terrane are wholly buried from sight, while the 
Gala terrane is present from base to summit, and subsides to the 
southward under the still higher group of the Riccarton and Balmae 
series (the Upland equivalents of the Wenlock and Lower Ludlow 
strata of Siluria). 
Roughly parallel with these two neutral lines (or axes of axes), 
to others less perfectly defined, and also to several gigantic strike- 
faults, the strata of the Scottish Uplands are ridged up into over- 
folds of all degrees of importance and complexity, from the crests of 
which the rocks of the Gala terrane, in many cases, have been 
removed, and the strata of the underlying Moffat terrane laid bare. 
The exposures of these pre-Gala strata usually occur in more or 
less connected areas, in broad boat-like patches, or in narrow dis- 
connected moniliform lines. These are disposed in broad geogra- 
phical bands or zones which range longitudinally through the district 
parallel with the chief axial lines. Three of these bands are 
especially conspicuous: (1) the 8.E. band of Wigtown, Moffat and 
Melrose (Moffat-Melrose band), (2) the central band of Port Patrick, 
Lead Hills and Lammermuirs (Lead Hills—Moorfoot band), and (8) the 
western zones of Ballantrae and Girvan. Tach of these bands is in 
1 Lapworth, Gzon. Mac. 18838, p. 188, etc. 
