34 Stewart — List of Estuarine Clay Fossils. 



Lucinopsis undata. Very large, and diffused in immense numbers 

 through the clay, except in the very oldest and very newest portions 

 of the bed. 



Tellina Balthica, Tellina solidula, F. & H. Abundant, especially near 

 the upper surface. 



Tellina tenuis. Near the top, only sparingly, and of small size. 



Tellina squalida, Tellina incavnata, F. & H. Very rare. The only 

 specimens I have seen were single valves collected by the late Wm. 

 Thompson, Esq., and by Mr. William Darragh, of the Belfast Mu- 

 seum. 



Psammobia Ferroensis. Single valves frequent, perfect specimens 

 rare. 



Psammobia vespertina. Mr. Grainger records finding a single valve of 

 this species. 



Mactra subtruncata. Frequent, variable in size and shape. 



Mactratruncata. Scarce. 



Lutraria elliptica. Frequent. 



Lutraria oblonga. One specimen, (fide Grainger). 



Scrobicularia alba, Syndosmya alba, F. & H. Scattered through the 

 clay in immense numbers. 



Scrobicularia pipe rata. Occupies the lower zone of the clay in the 

 greatest profusion, Rare 01 absent from the'higher or more recently 

 deposited portion of the bad. 



Solecurtis antiquatus, Solecuytis coarctatus, F. & H. A single speci- 

 men, (fide Grainger). 



Solen pellucidus. Distributed through the ^median portion of the bed 

 in abundance. 



Solen ensis. Occurs sparingly. 



Solen vagina, Solen marginatus, F. & H. Rather frequent. 



Thracia papyracea, Thracia phaseolina. Frequent ; shells often perfect. 

 The form T. villosiusaila also occurs. 



Thracia convexa. Perfect specimens of this fine shell are plentiful ; 

 their occurrence made it easy to recognise a well-marked zone of the 

 clay, replete with species that live mostly at a d2pth of five to ten 

 fathoms. 



Thracia pubescans. One specimen. (Grainger). 



Corbula gibba, Corbula nuc le us, F. & H. Plentiful, but mostly as single 

 valves. 



