160
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .Jan. 8,
and Dunrobin, the relations of the great series of estuarine beds to
the Liassic rocks cannot be seen.
In order to illustrate the variations in the thickness and order of
succession of these estuarine strata, I subjoin a number of sections
obtained by shafts and borings at various points, beginning in every
case with the " Boof-bed " — that is, the lowest bed (marine) of the
Middle Oolite (see fig. 15).
Fig. 15. — Comparative vertical Sections of the Coal-bearing Strata of
Lower Oolite age in Sutherland and Ross. (Scale 20 ft. to 1 in.)
Doll.
"Roof-bed of Coal" (equiva-j EiJigiiiJ
lent of Kelloway Rook) j I ^^~rj
.
Fascally. Inverbrora.
Cadh'-an-
Main seam of Coal
Highly carbonaceous shales
with thinner seams of Coal
(very variable)
Fire-clays with shelly bands,
bone-beds, &c '•.
Clays (greenish, whitish, and
black) with bands and no-
dules of argillaceous lime--.
stone and occasional thin
coal-seams
Sandstones below.
(1) Boring on shore at Inverbrora by John Pritchard, 1811 : —
ft. in.
"Roof bed" 4