199 
1916-17.] The Hurlet Sequence and the Abden Fauna. 
in the Blackbyre Limestone of the West of Scotland, while in the shale 
overlying it we have the Hurlet Alum Shale fauna. The shale is somewhat 
awkward to get at in this section, but both the brachiopod and the lamelli- 
branch bed appear to be present in their relative positions. Fish remains 
occur, but the existence of a bone bed has not yet been determined. The 
nodular and dolomitic encrinital limestone, No. 5, consists chiefly of 
encrinite fragments, the upper part being shaley and more evenly bedded. 
This is the equivalent of the brecciated limestone of the St Monans Section. 
The hard grey limestone with Productus giganteus, No. 10, is the same as 
Fig. 4. — Sketch Map showing Lower Limestone Series at Aberlady Bay. 
Based on fig. 7 in the Geological Survey Memoir on The Geology of East Lothian (1910). 
limestone No. 7 in the St Monans Section; and, lastly, the hard grey thick 
bedded limestone with encrinites and Productus giganteus , seen near 
Craigielaw Point, and the base of which is also seen in the Aberlady 
syncline, where it forms its highest bed, is the equivalent of limestone 
No. 10 in the St Monans Section, which we have shown to be the same as 
the Seafield Tower Limestone and the Charlestown and Petershill Lime- 
stone, that is, the Main Hosie Limestone of the West of Scotland. 
XI. Section at Dunbar. 
The last section which we describe is that exposed along the shore to 
the south-east of Dunbar, where the Lower Carboniferous Limestone Series 
is seen to be thrown into a synclinal trough, the basin being truncated on 
