2 
JOURNAL OF THE GEOLOGICAL SOCIETY OF DUBLIN. 
so for some time, this paper is brought forward as an accompani¬ 
ment to it, and to leave on record the different localities in which 
the fossils so described have been found, so that those localities may 
not be forgotten or lost. 
In considering how this should be done, it appears to me that a 
general Table is the most eligible form; this to consist of a list of 
the names of all the fossils in the Synopsis; the authority for the 
original name and description; the mineral character of the rock in 
which any fossil occurs; and a few of the chief localities whence 
each was obtained. 
After this Table will be an alphabetical list of all the localities 
in which fossils were found, amounting in number to about two hun¬ 
dred and eighty; giving the name of the place, with a short descrip¬ 
tion of the quarry or ravine in which the fossils occur, and its 
bearing and distance from the nearest post-town. Thus a person, 
having even a temporary residence in any town, may know the 
places of interest regarding fossils in his vicinity, and make further 
search, where a first and perhaps imperfect trial has been made 
before. 
As Mr. M‘Coy has changed the names of many of the old genera, 
and divided others, I deem it necessary to give the old names, which 
is done by means of letters of reference, and corresponding marginal 
notes. 
In the Carboniferous formation there are four kinds of rocks, 
distinct in mineral character; the lowest or first division of these 
is— 
1. Old Red Sandstone. 
2. Calcareous slate. 
3. Limestone. 
4. Coal-measures, being chiefly argillaceous shales and slates, 
with some sandstones and ironstones. 
Some of the fossils of the formation are found in sandstone, and 
not in any other of these divisions; some are peculiar to the cal¬ 
careous slate; some to limestone; and some are found only in the 
black mud deposits or slates of the coal measures. Again, some of 
the fossils are common to two of those mineral divisions, and some 
are found in three of them. The molluscous fossils of the Old Red 
Sandstone are very few and scarce, being mostly casts, and are in 
general not found in any other division. 
