Vinen, loc. cit.), with gallic and ellagic acids, ligneous fibre, water, and minute quantities of proteids, chlorophyll, resin, free sugar and, in the cells around the inner shelly chamber, calcium oxalate.
A further variation consists in the development of additional shelly plates upon the dorsal line between the two large valves (Pholadidae).
In Aspergillum the whole of the tubular mantle area secretes a continuous shelly tube, although in the young condition two valves were present.
The Lower, Middle and Upper Lias consist chiefly of shales and shelly limestones, with some sandstones, well seen along the shores of Broadford Bay in Skye and in some of the adjacent islands.
Few seas are more prolific in fish than the Persian Gulf and the Gulf of Oman; the great proportion of known species are edible and many have a commercial value for the isinglass or oil Shelly conglomerates and dead coral reefs of the littoral; red sandhills of the coast of Trucial Oman; alluvium of Turkish Iraq; river and lake deposits of Oman and the interior of Persia.