It may be necessary to cut out a small trench in front of the constructional hearth to allow the air pipe to be fitted.
The result is that the tracery itself has to support the structure above it - is, in fact, constructional - whereas in most other countries the tracery is merely, as it were, a pierced screen filling in a constructional arch.
The Conway quarries, four in number in 1908, are on either side of the Saco river, south-east and south-west of North Conway; their output is coarse constructional stones, all biotite or biotite-hornblende, but varying in colour, pinkish (" red ") and dark-yellow greenish-grey (" green ") varieties being found remarkably near each other at Redstone, on the east side of the Saco valley.
The surface soil is clay in which are embedded fragments of siliceous sandstone, used for millstones and constructional purposes; the subsoil is limestone.
The constructional choir is often wanting, the whole church forming one uninterrupted structure, with a continuous range of windows.