253 
on the Coast of Scotland . 
of a close subgranular structure, with interspersed grains of red 
felspar. This includes beds of coarse quartzy slate-clay, and 
fine sandstone conglomerate. This last seems to differ from 
the quartzy sandstone (or Quartz-rock as it is also called), 
chiefly in the grains being rounded, distinct, from a tenth to a 
twentieth of an inch in diameter, and connected by an alumino- 
siliceous cement, which is small in quantity, and easily decom- 
posed by the action of the weather. Higher up in the hill, the 
coarse, thick, slaty clay prevails, passing in several places into 
an irregularly granular, impure, yellowish- coloured limestone, 
with disseminated iron-glance. Above this the quartzy sand- 
stone again appears, until at the summit a dense slaty rock 
occurs, consisting of quartz and mica, which I was inclined to 
term slaty sandstone, from its connections w r ith the beds I had 
so recently passed over ; though, had I approached it through 
a gneiss region, I would, without hesitation, have pronounced it 
coarse mica-slate. In this last rock, portions of a coarse-grained, 
blue limestone occur, exhibiting some appearances of being a 
fine conglomerate. 
While employed in turning over some stones, in search of 
•marine animals, near low-water mark, I met with the Chiton 
laevis of Pennant {British Zoology , iv. tab. xxxvi. f. 3.), which 
he states as inhabiting the shores of Loch Broom. This species 
is the Chiton ruber of Fabricius, and other continental natural- 
ists. It is not the Chiton laevis of Montagu, described in Tes- 
tacea Britannica. The laevis of the latter author is distinguished 
from all the other native species (except the Ch. albus , with which 
it is not apt to be confounded,) by its reticular border, and from 
the laevis of Pennant, in wanting the longitudinal coloured 
band. Pennant’s shell is common on all parts of the Scottish 
coast. It is probably the Patella articulata cymbiformis of 
Wallace, (“ Orkney,” p. 41.), at least the figure which he has 
given is expressive of its ordinary appearance. The laevis of 
Montagu is of rarer occurrence. His specimens were procured 
in Salcomb Bay, Devonshire. I have found it in Bressay 
Sound, Zetland. Our specimens agree in every particular with 
those from Devon, which were sent to us from Mr Montagu 
several years before his death. While the Chiton laevis of Pen- 
nant must be considered as synonimous with ruber , the Ch. laevis 
