150 EDINBURGH PAST AND PRESENT.
stone quarries of Craigleith and Granton), several species of L~idodmdronan d
some. characteristic ferns, particularly the Sphojte~isa# nis and Adianfi2e.r
Lindserefomrj, and other forms. Some of the shales are charged with enfomustram
(Lqkdifia Smf&Bura‘zgdmk) and the scales, teeth, bones, and cop’rolites
of ganoid fishes such as PaZmnrjcus, Ewynofus, Megaiichfhys, and Rhizodus,
The marine intercalations are indicated by the presence of such forms as
Spirorbis, LinguZa, Schizodus, Myaiina, BelZ~rojhon, and Orfhoceras. Some
of the individual strata of this series are well known, either from their geological
or industrial interest. Thus the Burdiehouse limestone, long quarried
about four miles south from Edinburgh, is formed apparently from the
aggregation of the cases of little crustacea, chiefly of the genus Lcperdifia,
and has yielded a large number of well-preserved plants and fishes. The
ironstone nodules of the Wardie beach Are likewise noted for their fossil remains.
The sandstones of Craigleith, Granton, Redhall, Hunibie, and Binny have
supplied the best building-stones in this part of Scotland. More recently some
of the highly carbonaceous shales have been turned to account as profitable
sources of mineral oil.
Next in order comes the Carboniferous Limestone series, which in the
Mid-Lothian coal-field attains a thickness of 1220 feet. It consists chiefly of
sandstone and shales, with some bands of marine limestone and many valuable
skams of coal. Like the rest of this formation in Scotland, it was formed in
wide shallow lagoons, which at one time were covered with vegetation as the
mangrove swamps of the tropics now are, an’d at another, owing to the subsidence
of the ground, were submerged beneath salt water in which characteristic
marine forms of life abounded. The former condition is represented by the
coal-seams which consist of the compressed and mineralised vegetation that
grew upon the spot; the latter by the seams of limestone, full of crinoids,
corals, and brachiopods. Spines of various shark-like fishes, as well as scales
and teeth of others like the bony pike of the North American lakes, occur
actually on some of the coal-seams, one seam in particular being marked by
such an abundance of fish remains as to form a kind of ‘bone-bed.’ The
plants include the usual Carboniferous genera, as Eepidudmdron, Si@Za&,
Cdamites, Cordazh, Sphenojteris, Pecopierzk, etc.
The lower limestones are thickest. They may be seen at Gilmerton, and,
still better, at the great quarries of Cousland, Darcy, and Crichton. Their
fossils agree with those of the true ‘Mountain Limestone’ bf the centre and
northern English counties. The coal-seams form what is known locally as
the ‘ Edgecoal ’ series, from the fact that owing to a large dislocation which
