ch Eil. The diagonal system--represented by the great
valley itself, and known as the system of Ben Nevis and the Ord of
Caithness in our own country, and, according to De Beaumont, as that of
Mount Pilate and Cote d'Or on the Continent--was upheaved after the
close of the Oolitic ages. It was not until at least the period of the
Weald that its "hills had been formed and its mountains brought forth;"
and in the line of the Moray Firth the Lias and Oolite lie uptilted, at
steep angles, against the sides of its long ranges of precipice. It is
not so easy determining the age of the older system. No formation occurs
in the north of Scotland between the Lias and the Old Red Sandstone: the
vast Carboniferous, Permian, and Triassic deposits are represented by a
wide gap; and all that can be said regarding the older hills is, that
they disturbed and bore up with them the Old Red Sandstone; but that as
there lay at their bases, at the time of their upheaval, no more modern
rock to be disturbed, it seems impossible definitely to fix their era.
Neither does there appear among their estuaries or valleys any trace of
the Oolitic deposits. Existing, in all probability, during even the
times of the Lias, as the sub-aerial framework of Oolitic Scotland--as
the framework on which the Oolitic vegetables grew--no deposit of the
system could of course have taken place over them. I had not yet,
however, formed any very definite idea regarding the two systems, or
ascertained that they belonged apparently to a different time; and
finding the Lias upheaved against the steeper sides of the Moray
Firth--one of the huge furrows of the more modern system--I repeatedly
sought to find it uptilted also against the shores of the Cromarty
Firth--one of the furrows of the greatly more ancient one. I had,
however, prosecuted the search in a somewhat desultory manner; and as in
the autumn of 1830 a pause of a few days took place in my professional
labours between the completing of one piece of work and the
commencement of another, I resolved on devoting the time to a thorough
survey of the Cromarty Firth, in the hope of detecting the Lias. I began
my search at the granitic gneiss of the Hill, and, proceeding westwards,
passed in succession, in the ascending order, over the uptilted beds of
the lower Old Red Sandstone, from the Great Conglomerate base of the
system, till I reached the middle member of the deposit, which consists,
in this locality, of alterna