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thought could n ot have exhibited them in so flat a form but by 
some accidental means, such as growth or pressure betwixt 
two rocks : that either should be so constant or so pre- 
cisely regular, if admitted, would yet become an insure 
mountable circumstance, as they are found in a soft 
loose Clay on Shotover hill, which consists for the most 
part of an hardish Limestone, where numerous species of 
shells and animal remains, not compressed, are found, 
but none of these oysters; at least I could not find 
any of the same apparent species among the beds of stone. 
The species is most commonly known at Oxford, &c. as 
Heddington oysters : it is also found near Cambridge, 
Mr. Edward Bridgman found it at Lopham, in Norfolk, 
specimens of which were brought me by the Rev. Mr, 
Lambert. Miss Benett found great variety at Sandfoot 
Castle, near Weymouth, and favoured me with specie 
mens, some of which are deeper than usual. 
