IN THE UNITED KINGDOM AND FRANCE. 



169 



beds. In every case the copper was found in the body only of the oyster, 

 which it coloured blueish green, and not in the mantle or beard, which 

 was not green. In the green-bearded oysters which I have had an 

 opportunity of examining, the body was not green, and no trace of copper 

 could be detected in any part of the animal. The colour, too, was not 

 the same as that of the true copper oysters, but rather that which would 

 result from the deposition of chlorophyl or other similar chloroid 

 vegetable body in the cells. 



The sands and muds examined were from the following localities : — 



1. The River La Trinite, or Crach Auray, Department of 

 Morbihan. 



2. Marennes, Department of Charente. 



3. Arcachon, Department of Gironde.* 



1. The River Crouch, Essex. 



2. The River Roach, Ditto. 



3. Hay ling Island, Hampshire. 



1. Lough S willy, county of Donegal. 



2. Ballysadare, county of Sligo. 



3. Aughinish Bay, county of Galway. 



4. Roundstone Bay, Ditto. 



5. Traroe, county of Clare. 



6. Bally vaughan, Ditto. 



7. Besborough, north shore of the Estuary of the 

 Shannon, county of Clare. 



8. Carrig Island, south shore of the Estuary of the 

 Shannon, county of Kerry. 



Yalentia, county of Kerry. 



France. 



England. 



Ireland. 



9. 

 10. 



Sneem, 



Ditto, 



11. Foaty Island, county of Cork. 



12. Tramore, county cf Waterford. 



I shall follow the same order in describing the several specimens. 



France. 



1. River La Trinite, Auray, Department of Morbihan. — Sample of 

 mud from the best oyster ground, furnished by the Baron de Wolbock. 



Description. — Loamy alluvial mad, free from gravel, of a yellowish- 

 gray colour when dry. Grayish-blue externally, when fresh and moist ; 

 but of an intense black colour internally. Oxydized readily to a yellowish- 

 gray when exposed to air and light. When dry it formed a brittle, 

 friable, porous mass, not at all like plastic clay. When washed it left 

 a good deal of sand, consisting of quartz, minute fragments of felspar, 

 nuor, and spangles of mica, mixed with abundance of comminuted shells. 

 The washed clay was free from carbonates. The vegetable fragments 

 and plants intermixed with the clay belonged to : Zostera marina, Chor- 

 dina flagelliformis, Litosiphon pusilus, and, apparently, to a species of 

 Carpomitra. The remains of mollusca belonged chiefly to : Cerithium 

 reticulatum, Buccinum undatum, a species of Dentalium, apparently D. 

 tarentinum, a species of Astarte (A. Sulcata]), and young oysters. The 

 mud contained abundance of Diatomacea, Rhizopoda, and, apparently, 

 other microscopical organisms. 



The rocks along this part of the coast of France are granite, gneiss, 

 and lower palaeozoic slates and grits, a good deal altered. The sand, gravel, 

 and shingle of the coast are derived from these rocks. The fine mud 

 which serves to hold the sand together is a highly hydrated alluvial mud, 



* Some doubt having arisen as to the specimen from Arcachon being from that 

 locality at all, the description has been omitted. 



