Vol. 58.] | AMONG THE JURASSIC ROCKS OF SUTHERLAND. 297 
general dip in crossing this line. If it exists it must be pre-Jurassic, 
as the sequence of that series is very slightly interfered with on the 
shore. The boundary-line thus created runs a little south of Lothbeg, 
beyond which no Caithness Flags have been observed. This boundary 
is also very nearly that of any possible breccia-beds, which commence, 
as will be presently seen, a little north of the same place. Hence 
the local flags and the breccias are so far bound together, whatever 
it may be worth, by community of limit. 
So much then for the relations of the Caithness F lags an situ to 
the sea-stack and the fragments in the breccias. 
Til. Tue Ditsrrreurion or THE Brecora-Beps In THE UPPER 
JURASSIC SERIES. 
Commencing at the south, we find the basal sandstones of the 
Upper Jurassic Series at Allt-na-cuil, with conglomeratic portions, 
containing Lower Kimeridgian fossils, such as Ostrea deltoidea. 
The next succeeding recognizable horizon is found at the Lothbeg 
cutting. Here, at the bottom and sides of the railway-bridge, are 
massive grits with patches of black shales, which represent no doubt. 
the uppermost portion of the lower beds. These are followed by 
two alternations of bands of shale and massive grit, above which is a 
thicker series of shales, yielding Cardioceras alternans and Belemmtes 
spicularis in abundance, and thus indicating the recognizable horizon 
of C. alternans. The bands of grit here are perfectly normal, they 
have a gentle dip in a northerly direction, and there is no sign of 
brecciation. 
The lowest grit-band seen at the railway-bridge keeps the shore 
as far as Craigie Point, on turning which we find on the scars 
indurated thin bands, 1 inch and less in thickness, with very little 
indurated grit; but the fossils are Cardioceras alternans and Aucella 
Pallasi (?= Avicula vellicata). These are in the line of strike 
determined at the bridge. 
*Passing northward, we have a considerable interval to traverse 
before scars again appear ; though when they do, the strike of the 
beds exposed is the same as before, but they are more sandy. They 
are not, however, repetitions of the lower grits of Lothbeg, as 
represented on the Survey Map, being soft and white, or with very 
carbonaceous intervening shales, almost as black as coal; and, more 
particularly, they are not followed by C.-alternans beds, but by 
fossiliferous shales, characterized by the presence of Hoplites eudoxus 
or one of its allies, the horizon of which is near the base of the Upper 
Kimeridgian in Kimeridge Bay. In these shales the strike can be 
seen and traced continuously nearly parallel to its constant direction, 
only changing by the thickening and thinning of the lenticles of 
grit. Above and with the Hoplites-shales are the most abundant 
remains of leaves, ferns, etc. Everything here seems perfectly 
regular, without any disturbance or break. The whole might be, 
in general, matched in Kimeridge Bay itself. 
