168 Recent EXcaVvATIONS AT BIRRENS. 
ticularly in respect of the manner of dressing the facing-stones. The 
materials used are the freestone of the district with lime mortar. 
Limestone is abundant in the vicinity, and the traces of mortar 
in the walls, although meagre, sufficiently establish its use. The 
facing-stones of both sides of the primary walls are headers, squared 
and arranged in regular courses, generally 6 inches to 7 inches 
hieh, and in lengths of 9 to 18 inches, and the centre is closed with 
stones fitted in between the headers. As showing the excellence 
of the work, it may be mentioned that in the case of No. IV. even 
the dwarf walls are so built. 
Some specimens of bonding found are typical. One consists 
of freestone flags about 24 inches thick laid in the wall, so as to 
extend across its thickness and form a continuous course in its 
length. The best example remaining is in the north wall of No. 
XI., where it forms the seventh course above the foundation (see 
drawing, plate IIIA.). Bonding bricks appear also to have been 
used, for, although not found in position, numerous fragments of 
such are scattered about. 
The manner of dressing the stones exhibited is various ; 
generally the inside faces of the walls are scabbled, and in many 
cases the outside faces are similarly dressed. The dressing of the 
external face of the front wall of No. IV. is the most character- 
istic. The stones show diagonal lines forming a reticulated or 
diamond pattern of half-inch to inch mesh within a chiselled margin. 
This wall is of superior and artistic workmanship, and the great 
care bestowed cn it is doubtless due to its prominent position in 
the main street. Appearance being less essential in other locali- 
ties, less elaborately dressed work is made to suffice. 
It now only remains to notice the indications of architectural 
treatment afforded by the vestiges. That appearance was an 
element in the design is sufficiently attested by the use of superior 
and more elaborately dressed masonry in the most prominent 
situation—the main street. From this, too, it may be deduced 
that the great display of buttresses, with their splayed and neatly 
hewn base course, while intended chiefly to secure strength, were 
probably likewise utilised to promote architectural effect. The 
arcade of the praetorium already described is an architectural 
feature, and a variety of fragments remain indicative of the exist- 
ence of others, and of artistic surroundings. 
