286 
Proceedings of the Royal Society of Edinburgh. [Sess. 
H.M.S. “ Knight Errant.” 
Station 3. 3rd-4th August 1880. 
Lat. 59° 12' N., long. 5° 57' W. ; depth 53 fms. 
The material from this Station consists of about 25 lb. weight of sand, 
with pebbles from a little over the size of sand-grains up to nearly 3 inches 
in longest diameter, and a lot of decayed shells. The largest stones appear 
as if they had been glaciated, but had been subsequently scrubbed and 
polished by the passage of sand, the joint faces being still apparent. The 
smaller stones appear to have been rolled, but only those under \ inch in 
diameter. Organisms such as polyzoa and serpulse are still attached to 
them, sometimes on all their sides, but more frequently one side is bare of 
them, showing that they had lain on, or had been partially embedded in, 
the sand. Numerous shells of sublittoral or shallow- water habitat, such as 
Pecten, Astarte, Mactra, Pectunculus, Aporrhais , Fusus, and Trochus 
occur plentifully with the sand and stones. All were dead when dredged. 
Only a few of the valves of the lamellibranchs are whole, and none to- 
gether. Most of them are thoroughly riddled with boring sponges and 
much decayed by solution, suggesting that they are not in their natural 
habitat. Only the calcareous tubes of Ditrupa, a tubicolar worm, are fresh, 
as if the animal had been living when caught by the dredge. 
A very large proportion of the stones from this locality are of sedimen- 
tary origin. The Torridonian rocks are represented chiefly by dark choco- 
late-coloured arkoses with pebbles stained red. Some are coarse-grained 
and epidotic, but most of them are fine-grained. There are 43 fragments 
above 1 inch in diameter, the largest only 1J inches, while there are no 
less than 142 fragments below 1 inch. None of the fragments is well 
rounded, but all are polished as if by attrition of sand. To this formation 
may also belong ten small pebbles of red-stained gneiss, probably derived 
from a red conglomerate. There are 22 small specimens of quartzite, 
presumably of Cambrian age, one or two of which are somewhat rounded, 
the others are like glaciated stones that have had their markings obliterated 
by sand. The Cambrian quartzite passes out to sea at the mouth of Loch 
Erriboll on the north coast of Sutherland. 
The Old Red Sandstone is mostly represented by over seventy fragments 
of the characteristic and unmistakable “ Caithness flagstones,” some of 
which are calcareous. The largest is below 2 inches in diameter, but the 
majority are under \ inch. Were specimens below \ inch to be counted, 
hundreds of fragments of these flagstones would have to be recorded. 
