THE BORROW!) ALE SERIES AND THE CONISTON FLAGS. 479 



rocks west of Millom, that its occurrence might be looked for in 

 Ireland, where rocks appertaining to the Bala series are seen. 



On the coast of the co. Dublin, the nearest locality where such 

 rocks could be expected to appear, they are absolutely seen in the 

 direct line of strike of the Coniston Limestone of the north-west of 

 England. 



On Lambay Island, two and a half miles east from the mainland, 

 in the south-east portion of the island, we have part of the Coniston 

 series forming a synclinal, though exhibiting many of the same 

 features and the same fossils which this group of rocks in the Lake- 

 district aifords. Here are grey limestones succeeded by concre- 

 tionary bands called by Mr. Du JSoyer • " coarse Conglomerates " 

 (Explanations of Sheets 102 & 112 of the Maps of the Geological 

 Survey of Ireland). This "Conglomerate" is described as "com- 

 posed chiefly of rounded pebbles and boulders of grey Silurian 

 Limestone, either fossiliferous or not, with fragments of dark cleaved 

 state, grey grit and greenish grey greenstone, and ash : in one 

 instance a boulder of an older Silurian Conglomerate was discovered, 

 in which were rolled pebbles of a dark green close-grained green- 

 stone, the base being a grey limestone containing Silurian fossils." 

 (Note by Mr. Jukes : — "Some of the Silurian corals were attached 

 by their bases to the pebbles, showing that they had grown on them, 

 just as corals may now be seen growing on pebbles or fragments of 

 rocks along a tropical shore.") " The matrix of the Kiln-Point 

 Conglomerate is a black mud ; and throughout the deposit are irre- 

 gular slaty layers." " When we get lower into the mass we lose 

 the conglomerate, and find nothing but pure dark grey slates, which, 

 near Raven's "Well, are found to contain Graptolites and thin calca- 

 reous fossiliferous bands " (p. 48). 



It is also stated that at Kiln-Point the " grey Silurian Limestone 

 is a wedge-shaped mass of lumpy la3*ers, with thin bands of dark 

 grey earthy shales between them, all very much contorted and 

 resting on the porphyritic greenstone, which has evidently come up 

 under them while in a pasty condition from heat, as it sends veins 

 and strings into the lower beds of the limestone, and often enclosing 

 fragments derived from it." Other circumstances indicate volcanic 

 activity during the deposition of these limestones, even to a greater 

 extent than has been recognized in the Lake-district. 



These limestones have below them rocks intimately related to 

 those of the Borrowdale series of the north of England, which are 

 doubtless the equivalents of the latter. 



At Portraine, on the mainland, immediately opposite Lambay, 

 there is seen, on the coast, one of the finest sections of the Coniston 

 Limestone and its associated rocks which occurs in the British Isles. 



Portraine is about two miles east of Don abate Station, on the 

 Dublin and Drogheda Railway. On reaching the coast an exposure 

 of rock is seen a little east of the coast-guard station. This consists 

 of a purple conglomerate, largely made up of quartz pebbles, which 

 has been designated Old Red Sandstone ; but it is more probably 

 the basement conglomerate of the Carboniferous formation. As 



