200 Scientific Proceedings, Royal Dublin Society. 
deficiency was very soon to be filled up. His Upper Secondary is 
Magnesian Limestone, New Red Sandstone, Black Shale, Lias, 
Greensand, and Chalk. Griffith knew of the Silurian fossils that 
Portlock had obtained in the small slate area on the N.E. side 
of Pomeroy, in Tyrone; but Portlock’s memoir was not yet out, and 
Griffith not wishing to ignore Portlock’s discovery, but still 
afraid of being too hasty, left the small space uncoloured. 
The map of which we have been speaking was dated April 
28, 1838. Very shortly after that, in the same year, the large map, 
which had been ordered by the Government, in 1836, to be re- 
constructed and engraved, was brought out; though, for some 
reason which does not appear, it was not regularly published, so 
as to be accessible to all, until March 28, 1839, the date which is 
inscribed upon it. A copy of this was exhibited to the British 
Association, at Neweastle, in August, 1838, after hanging for 
some time in the rooms of the Geological Society of Dublin. We 
must guard against confusing these two maps of 1838 together ; 
a mistake which was made by some contemporaries, and gave rise 
to great misunderstandings. The large map must have appeared 
very shortly, indeed, after the one we have just been considering ; 
and yet it contained two very important changes, one of them 
apparently of a very daring character. It gave the Old Red 
Sandstone of Middle and East Cork, Waterford, and Kilkenny, as 
such, instead of what it had been supposed to be, viz., Newer 
Transition (Upper Silurian). And the Carboniferous Slate within 
the root of the Dingle Promontory and that of South Cork was 
now first made such, instead of what it had been supposed to be, 
Older Transition (Lower Silurian, or Cambrian). These changes 
were contrary to the opinions of Portlock, John Phillips, and 
other geologists, and they were strongly epposed by the admir- 
able and veteran Weaver. They have since, however, been amply 
justified by the Geological Survey. We ought to mention here 
that in 1836 Mr. Charles W. Hamilton, sometime Secretary and 
afterwards President of our Society, pointed out to Griffith that 
the rooting slates which they together saw quarried at Ringa- 
bella, a little outside the entrance to Cork Harbour, were newer 
than the O.R.S. Before any fossils were discovered in the sup- 
posed Greywacke of South Cork the mistake that had been made 
by all the authorities, Griffith himself included, respecting those 
