of the building. These exist at Lichfield
with their spires; they exist (square-topped) at Lincoln, and (though
carried up since the Gothic period) at Westminster.[13] Many churches
have a single tower in this position (Fig. 13).

The obvious purpose of a tower, beyond its serviceableness as a
feature of the building and as a landmark, is to lift up a belfry high
into the air: accordingly, almost without exception, church and
cathedral towers are designed with a large upper story, pierced by
openings of great size and height called the belfry stage; and the
whole artistic treatment of the tower is subordinate to this feature.
It is also very often the case that a turret to contain a spiral
staircase which may afford the means of access to the upper part of
the tower, forms a prominent feature of its whole height, especially
in the Dec. and Perp. periods.

[Illustration: FIG. 12.--LINCOLN CATHEDRAL. (MOSTLY EARLY ENGLISH.)]

In domestic and monastic buildings, low towers were frequently
employed with excellent effect. Many castles retained the Norman keep,
or square strong tower, which had served as the nucleus round which
other buildings had afterwards clustered; but where during the Gothic
period a castle was built, or rebuilt, without such a keep, one or
more towers, often of great beauty, were always added. Examples
abound; good ones will be found in the Edwardian castles in Wales (end
of thirteenth century), as for example at Conway and Caernarvon.

_Gables._

The gable forms a distinctive Gothic feature. The gables crowned those
parts of a great church in which the skill of the architect was
directed to producing a regular composition, often called a front, or
a facade. The west fronts of Cathedrals were the most important
architectural designs of this sort, and with them we may include the
ends of the transepts and the east fronts.

The same parts of parish churches are often excellent compositions.
The gable of the nave always formed the central feature of the main
front. This was flanked by the gables, or half-gables, of the aisles
where there were no towers, or by the lower portions of the towers. As
a rule the centre and sides of the facade are separated by buttresses,
or some other mode of marking a vertical division, and the composition
is also divided by bands of mouldings or otherwise, horizontally into
storeys. Some of the horizontal divisions are often strongly marked,
especially in the lower