A LIST OF THE 
Fossils of the Estuarine Clays of the Counties of 
Down and Antrim . 
By SAMUEL ALEX. STEWART, 
Fellow of the Botanical Society of Edinburgh, Hon. Assoc, of the 
Belfast Nat. Hist, and Phil. Soc. 
The term, Estuarine Clay, is intended to signify those deposits, mostly of 
clay, which have been accumulated in our existing bays and estuaries since 
the close of the Glacial Period. They are the latest of the long series of 
geological deposits, and resting, as they most commonly do, on the 
Boulder Clay, they unite the present to the past. 
The Estuarine Clay often presents beds of considerable thickness, which 
have been continuously laid down, and are tenanted by the shells of 
species that have lived and died on the spot. It is to be regretted that these 
beds have not received more attention, as they offer perhaps the best means 
of filling up the gap in geological history between the close of the Glacial 
Era and the present. 
These Estuarine Clays are widely spread in Britain, being of consider- 
able thickness, and covering areas of some extent in such important 
estuaries as those of the Clyde and of the Mersey. In the North of 
Ireland we have several of these beds. That at Belfast exceeds twenty 
feet in thickness, and is spread over an area of at least four or five square 
miles. It may be seen at Belfast, Sydenham, Holywood, Bangor, and 
Kilroot. Similar, though apparently less extensive Post-Pliocene accumu- 
lations, are to be found on the shores of the Loughs of Larne and Strang- 
ford, and also at Lough Foyle, and near Coleraine. Of the two latter no 
detailed account has been published, and I have had no opportunity of 
