204 Scientific Proceedings, Royal Dublin Society. 
was engraved, by order of the Lords of the Treasury, and pub- 
lished. No change has been made in it since then. 
In January, 1856, a copy of this map was presented to the 
Geological Society of France, and was demonstrated to the 
meeting by M. Elie de Beaumont. 
In 1857 the new edition of the map was exhibited to the British 
Association in Dublin, and Griffith gave then a paper, and sub- 
sequently another to the Geological Society of Dublin, in which he 
considered certain rocks below the base of the Carboniferous sys- 
tem—that is to say, the Dingle Beds and Glengariff Grits, in the 
South, and the Croagh Moyle, Curlew Mountain, and Fintona 
rocks in the north, all of which he believed to be ef somewhat 
similar age. His opinion regarding the Dingle Beds and Glen- 
gariff Grits hadnearly always been substantially the same from the 
first; he made them Upper Silurian. As the question of the age 
of those rocks was under consideration by the Geological Survey 
he took that opportunity of bringing up the subject. He had 
examined those rocks again in the preceding year in company 
with Jukes, Murchison, and Salter. We all know that Jukes 
finally concluded that there was least difficulty involved in making 
those rocks Old Red Sandstone, and that he coloured the Glen- 
gariff Grits as such on the Survey maps, though he left the Dingle 
Beds provisionally with an indecisive colour. We are told that on 
the occasion just mentioned Murchison was inclined to side with 
Griffith, although Murchison and Phillips, after visiting together 
the Dingle Promontory in 1843, immediately after the meeting of 
the British Association in Cork, had concluded that those rocks 
were Old Red Sandstone. 
Griffith, then, observes that, as he expresses it, the Glengariff 
Grits in the Dingle Promontory lie conformably on fossiliferous 
Upper Silurians, and are covered unconformably by the O. B.S. 
Stratigraphically, therefore, they are more closely connected with 
the Upper Silurian. Besides this there is the occurrence of simi- 
lar felstones and ashes in the Silurians and in the Glengariff Grits 
of Dingle. There is, therefore, a double probability in favour of 
those Grits being Silurian rather than “Devonian.” But the 
Glengariff Grits N. and 8. of Dingle Bay are identical in character, 
and seem to belong decidedly to the same series of rocks. It is 
true, indeed, that on the 8. side of Dingle Bay the O. R. S. lies 
