Lapworth & Wilson — Silurian Rocks of Roxburgh & Selkirk. 461 



There is also anotlier conglomerate made up of millions of little 

 white quartz pebbles, very like that of the Winkstone Quarry, and 

 which is traceable in four distinct lines to the north of the pebbly 

 grit. This conglomerate contains both rounded and angular pieces 

 of the Moffat shale, often full of its characteristic graptolites. Some 

 of these fragments are much altered, and fiill of little quartz veins, 

 and exactly resemble the little pebbles of the altered Moffat shale 

 now found in the burns ; proving that in some localities, at least, 

 the anthracite beds must have been hardened into rock, upheaved, 

 and greatly altered before this conglomerate was deposited. The 

 first line appears to cap the Grieston slates throughout, the second 

 runs across the hill tops between Fountainhall and the Luggate 

 water, for a distance of six or seven miles. The third appears a 

 little to the north of this, and at the cottage of Ladyside, and the 

 fourth runs parallel with the anthracite down the south bank of the 

 Heriot. There are also thin bands of carbonaceous shale that run 

 on for many miles, more especially towards the bottom of the group. 

 The fossils of the G-ala group include : — 

 Biplograpsua palmeus, Barr. Graptolithus socialis (n. sp.). 



,, bullatus, Salter. ,, getmnatus, Barr. 



Graptolithus priodon, Bronn. Rastrites Linncei, BaiT. 



„ colonus, Barr. RetioUtes Geinitzianus, Barr. 



,, Sedgwickii, M'Coy. ,, obesus (n. sp.). 



„ Sagittarius, His. Dictyonema (sp.). 



„ lobiferus, M'Coy. Ceratiocaris (2 species). 



„ Salteri, Geinitz. Aptijclwpsis (2 species). 



„ Griestonensis, Nicol. Peltocaris aptychoides. 



,, Nilssoni, Barr. Annelidte, such as Crossopodia. 



„ turriculatus, Barr. Nereites, and many others. 



The fauna is, as a whole, remarkably different from that of the 

 Moffat series. About 9-lOths of the .Graptolites of the anthracitic 

 band have disappeared, the branching forms all extinct, and their 

 place is usurped by the mono-grapsus, which is specifically unimpor- 

 tant in the Moffat beds. This change is very sudden, as nearly the 

 whole of the peculiar Gala forms may be collected within a few 

 yards of the anthracitic band itself, both in the neighbourhood of 

 Galashiels, and apparently also on the Douglas water. The great 

 alteration in the fauna cannot be due to a change in the condition of 

 the sea-bottom, for the beds from which the lowest Gala species are 

 obtained are black carbonaceous shales, of a foot or two in thickness, 

 with an out-crop that seems to be continuous for nine or ten miles at 

 a stretch. 



The great majority of the Gala species run from the base to the 

 summit of the group, proving the unity of the whole, but rendering 

 it utterly impossible to subdivide the strata by means of the fossils. 



For these and many other reasons, which time will not allow us 

 to discuss here, we consider that the Gala group is a distinct and 

 single division of the Silurian rocks, commencing immediately above 

 the anthracite bed of the Moffat series. 



One fact should here in honesty be stated concerning the Gala 

 beds. The rocks of the group to the north of the Grieston slates 

 have, as a whole, a different appearance from those lying to the south 



