shell
A kidney-shaped section occurring in the butt area
of an equine animal hide which contains the dense
mass of fibers known as the glassy layer. The
collagen fibers of this area are so dense (perhaps
the most dense of any leather) that the leather
made from it is nearly air-tight and weatherproof.
It is isolated by removing the skin layer above
and below it. The remaining part, the shell, is
frequently split, both splits being finished on
the cut surfaces. Although the butt area of the
hide is extreme in its tightness and solidity of
structure for a large hide, the remainder of the
hide is extremely loose. The shell is used in
producing CORDOVAN
LEATHER . (363 )