THE HAMILTON ASSOCIATION. on 
entitled to a distinct family classification,) were undoubtedly repre- 
sented in Palzeozoic times by Molluscs bearing at least externally, 
I cannot say a close, but certainly a resemblance to the shells of 
tropical or sub tropical seas of our own days. Prervinea Demissa and 
Ambonychia Radiata, so frequently found in Cambro-Silurian drift 
pebbles and shingles, here are supposed to come under this head, as 
as also Fosidonomya, Posidonia and two or more specimens from the 
Barton Niagaras. So/emya, a shell yet living in the Mediterranean, 
also dates from Palzeozoic times. 
PECTEN, SCALLOP OR COMB-SHELL, 
Nearly related to the foregoing, although included among the 
Ostracidae by Woodward in ‘‘ The Manual of the Mollusca,” are the 
Scallops. Three species occur in the lower Carboniferous of Ireland 
now known by the name of Aricula pecten, McCoy. One, 4. 
Sowerbi, still retains its wavy zig-zag bands of amber color in the 
mountain limestone beds. I had not the good fortune to collect a 
single example of this beautiful and very rare fossil, although I 
succeeded in securing many of the characteristic ones figured in the 
late Professor W. H. Baily’s work. A quarry near Templemore, 
Tipperary, afforded me some of the best preserved organic remains 
such as limestones seldom yield. I never possessed, I believe, even 
average skill in extracting such things from the matrix. But then, 
owing to the soft nature of some of the layers, I found little difficulty 
in obtaining almost perfect casts of well known Palzozoic shells, 
with one exception, Orthoceras. The modern Waticas and Pyra- 
mydellide were also represented by species in the mountain limestone 
of Cork and Limerick, the latter by a Loxonema. Pleurotomaria 
occurs in the carboniferous rocks and WVautilus Dorsalis, Phillips. 
The last, however, I did not get. No doubt I may have omitted 
other families that can be traced to Pleeozoic times. 
Independent of a few shells, whose position is yet unsettled, 
the Echinus or Sea Urchin was represented by Palechinus Elegans, 
McCoy. I did not obtain even a spine in the quarries I examined. 
BRACHIOPODS. 
While I feel I am reversing the order of their appearance, this 
necessarily follows in the course we take in any attempt to link the 
