166 SILUKIA. [Chap. VIII. 
abundant traces of Annelides — both the large Scolithus linearis (Quart. 
Journ. Geol. Soc. vol. xv. p. 368) and the minute shelly Annelide which is 
here figured. 
Fossils (28). Annelide-tubes from the North-western Highlands op Scotland. 
Small, thick, shelly tubes 
of Annelides (Salterella 
Maccullochii, Salter). 
Collected from the Lower 
Quartz-rock of Durness, 
Sutherland, by Mr. C. 
Peach. 
Although the tube of this Salterella (Billings) is thicker in proportion 
than in any known Serpulites, it was provisionally referred in my last edi- 
tion to that genus, and named, at my request, Serpulites Maccullochii by 
Mr. Salter, after the distinguished geologist who first noticed it *. 
These fossil-bearing beds of Sutherland are clearly and conformably 
covered by other crystalline rocks, whether consisting of quartzose mica- 
schists and flagstones or younger strata having the characters of gneiss. 
One of the chief objects of my last visit to the Lower-Silurian limestones 
of Durness and Assyntf was to be satisfied, by another appeal to nature, 
that there were qnartz-rocks above as well as below the fossiliferous lime- 
stone. Such a succession, followed symmetrically upwards by mica-schists, 
flagstones, and a younger gneiss, was again seen on the eastern side of 
Loch Eribol, where that physical order was observed thirty-one years ago 
by Sedgwick and myself. In 1859, in company with Professor Bamsay, I 
traced the same relations from Loch Eribol on the 1ST.N.E., along interve- 
ning spots to the east end of Loch Stack and the western end of Loch More, 
and again in tracts lying on and to the east and south-east of Loch Assynt, 
— a distance along the strike of not less than forty miles from JLET.E. to 
S.S.W. Another proof of the soundness of this general view is seen in the 
fact that when the older or fundamental gneiss reappears amidst the over- 
lying strata, as between Loch Durness and Loch Eribol, it throws off 
quartz-rocks and limestones to the N.W., and places them in a basin, — a 
fact observed by Mr. Peach, but which escaped the notice of former ob- 
servers. Now, if the fundamental gneiss had been thus protruded to the 
surface in other and more eastern places, similar reversals of the dip might 
have been looked for ; but no such basin-shaped arrangements are seen to 
the east of the tracts where the order of succession has been described; and 
* Speaking of these obscure little fossils, in a Crustacea on the Kyle of Durness are now dig- 
Lecture on the Geology and Scenery of the North ging in the sand washed out of these very rocks, 
of Scotland (1866), Professor J. Nicol says (p. 31), The same sand is now lying in the same place, and 
" In the quartzite period organic life undoubtedly beings of like organization are still burrowing it 
existed. Twoscore years ago Dr. Macculloch out for food or shelter. Yet the mind almost 
pointed out curious conical hollows, ending in refuses to grasp the myriad ages that have inter- 
long pipe-like bodies. These he described as vened. The poor worm or insect in its daily occu- 
Worm-holes, the prototypes of those seen on the pation was building itself a monument ' sere pe- 
ehore, where the Lobworm sinks into the sand rennius' — a tomb more enduring than king or 
left dry by the retiring tide (Geol. Trans, vol. ii. kaiser. The moral needs not be drawn." 
p. 461). We have seen other, smaller holes iden- t Orthoceratites have been detected by Mr. 
tical in form with the holes which some small Peach and myself in Assynt. 
