Chap. VIII.] 
SILURIAN ROCKS OF SCOTLAND. 
151 
section to the Cheviot Hills on the south, and a very long one to the 
Pentland Hills, near Edinburgh, on the north. 
This traverse shows in the clearest manner an upward development from 
the lowest divisions of the series ; so that, after placing other transverse sec- 
tions in parallelism with it, whether along the east coast or from Dumfries 
and Moffat, we will then pass to the west coast, where we meet with 
higher and much more fossiliferous masses of the Silurian system. 
Casting his eye over the foregoing diagram*, the reader will understand 
the comparison which is drawn between these Scottish strata and those of 
the typical region of Siluria and Wales, described in the second, third, and 
fourth Chapters. 
Beginning with the rocks which form the axis of Roxburghshire and 
Dumfriesshire, it is seen that they are of purplish or dull red colours, and 
that, whether sandstones or alternating purple and grey schists, they are 
absolutely of the same composition as the bottom rocks of the Silurian re- 
gion. Until a few years since, no fossils had been found near this Scottish 
basement rock; but in 1854 Sir W. Jardine detected Protovirgularia in 
purplish shale which, in the parish of Applegarth, lies immediately to the 
south of the axial line. At Binks in Roxburghshire, about three miles 
N.E. from Moss Paul Inn, and in the same range, Professor Harkness 
observed physical evidences of deposits formed in very shallow water, in 
the ripple-marks, cracks of desiccation, and fine alternations of sand and 
mud. On one of the grey-Coloured layers of the latter he detected in 1855 
the track of a Crustacean^ a drawing of which is here given, it being the 
Fossils (24). Track of a Crustacean. 
Protichnites Scoticus, Sal- 
ter ; from Binks, Roxburgh- 
shire. Half the natural size. 
Impressions of the feet and 
of the sternal or the caudal 
portion of the body. 
earliest sign of animal existence which we have obtained in Scotland. The 
creature which left these markings was possibly a shrimp -like Crustacean, 
as suggested by Professor Harkness, and analogous to the Hymenocaris 
(Salter) of the Lingula-flags, of which a sketch is given (p. 44), The cu- 
rious impressions above figured are not at all unlike those far larger prints 
which Prof. Owen has so well described, and which were found by Sir W. 
E. Logan in the Potsdam Sandstone of Canada (Quart. Geol. Journ. vol. 
viii. p. 214). In this case, however, it would appear that a single pair of 
eyin 
the Pentland Hills 
* Eeduced from a large coloured section exhi- 
bited at the Belfast Meeting of the British Asso- 
ciation for the Advancement of Science, 1852. 
Since this section was made, the region at its 
north-western end has been the subject of a de- 
tailed survey by Mr. G-eikie ; and he has given a 
section conveying the true relations of the rocks in 
Society of Edinburgh, vol. v. p. 350.) This section 
■See Proceedings of Eoyal 
shows how the Lower Silurian are succeeded by 
strata containing Wenlock and Ludlow fossils. 
