The universal geography : earth and its inhabitants

14 THE BRITISH ISLES.
Farther west still, amongst the many bays which indent the coasts of Devon
and Cornwall, the foremost place belongs to Plymouth Sound, which ranks with
Chatham and Portsmouth as a great naval station.
If we now turn to a consideration of the principal features of Ireland, we
shall find that they differ essentially from those presented by the more favoured
sister island. Less varied in its contour, it exhibits likewise greater simplicity in
Fig. 8.—PLYMorTH Sound and the Hamoaze.
From an Admiralty Chart. Scale 1 : 150,000.
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its geological structure. Broadly speaking, it may be described as consisting of a
great central plain of carboniferous limestone, stretching across from sea to sea,
and bounded in nearly aU directions by mountain masses composed of the most ancient
geological formations.* The highlands of the north-east, north-west, and west
consist of the same crystalline and Silurian rocks which are so extensively developed
in Scotland. The south-eastern highlands likewise consist of Silurian strata pene-
trated by granite, and overlying Cambrian rocks, thus repeating the features which
• E. Hull, "The Physical Geology aud Geography of Ireland."