i86 
THE ESSEX NATURALIST. 
Bohuslan oyster and others from N. Jutland agree with our 
North Sea Hasborough shells in having a more efflorescent 
lamination than is usual with the East coast oyster. 
The “ human ” history of the subject goes back to the caves,, 
middens and shell-banks of Azilian and later days, on the northern 
coasts at Dunagoil, Colonsay, Oransay, Ardrossan, Caithness, the 
Shetlands, N.E. Scotland and elsewhere. Many of these are 
of large size. Of two mounds on the shores of' Loch Spynie,. 
one measures 240 by 90 feet, the other 178 by 90 feet. Another 
at the Creggauns in Co. Galway (more recent) is nearly as large. 
That at Oronsay has been beautifully described and illustrated 
in Pr. Soc. Antiq. Scotland, vol. 48, p. 52, by Mr. Henderson 
Bishop, to whose courtesy I owe a fine series of valves (Plate xii., 
fig. 1). The mound of Cnoc-sligeach in Oronsay now stands 
some 35 feet above the original sea-level, and according to 
Prof. Scott Elliott was accumulated 6000 years B.C., when 
the hunting tribes, finding flesh-meat to be getting scarce, took 
to fishing. The shells are of large dimensions, one measuring 
120 by no mm. The lamination on the top valve is very closely 
set and flattened ; on the lower valve the ribs are very strong 
and equal in thickness to the interspaces, with a shallow ligamentaL 
area, slightly curved but of moderate breadth and length. 
The genus has now died out in this district, but at Colonsay 
banks of dead shells may be seen on the beach between tide marks. 
The value of the British oysters as food became apparent 
to the Roman settlers in Britain as early as A.D. 50, and there is 
hardly a Roman site, station, or town where the shells are 
not present in abundance. The small Rutupinian mollusc was 
the one mostly in demand for exportation, but the Romans 
also utilised the larger and deep sea form whenever procurable,, 
especially at Verulam, Folkestone and about London. The 
shells found in the dwellings of this people are a very good 
index to the type of shells then living on the nearest coast line ; 
thus at Silchester they are of the Channel or Southampton type, 
at Caerwent and Uriconium they are of the larger or Welsh 
series, and on the Eastern coast mostly Rutupinian. 
Our Saxon forefathers do not seem to have been interested 
in Oysters, as their shells are seldom or never found in or about 
Saxon sites. 
Although the oyster was abundant all round our coasts prior 
