150 
JOURNAL OF THE GEOLOGICAL SOCIETY OF DUBLIN. 
sandy limstones, alternating with gray flaggy sandstones and shales, 
which are literally covered with fragments of fishes’ teeth; and these 
beds are again succeeded by others containing abundant casts of 
fucoids. The total thickness of the fish teeth and fucoid beds is 71 
feet. 
The remainder of the older limestone beds of this district which 
underlie the dolomite beds, are composed of flaggy limestones, with 
black shaly partings, and alternating layers of blue shaly limestone. 
The total thickness of the series, including the two groups al¬ 
ready mentioned, is 851 feet. About the middle of the series, a band 
of fine shaly limestone occurs, under Loftus Hall, which contains an 
extraordinary abundance of two varieties of Carboniferous Trilobites, 
viz., Phillipsia gemmulifera and P. quadriserialis. 
The entire group is terminated on the south, and overlaid by. a 
band of dolomite limestone, extending from the rocks at the south 
point of Patrick’s Bay on the east to a point about 300 yards S. W. 
of Duffin’s Well on the west or harbour side. 
The older limestone, like the newer limestone which lies above 
the dolomite, is marked by a profusion of fine fossils, of which the 
commonest are—- 
Fenestellidse. 
Milleporidse. 
Favosites megastoma. 
Lithodendron pauciradiale. 
Syringopora geniculata. 
Spirifer clathratus. 
„ attenuatus. 
,, plebeius. 
Leptsena analoga. 
Orthis filiaria. 
0. crenistria. 
Athyris concentrica. 
A. squamosa. 
*Orthoceras attenuatum. 
*Euomphalus pentangulatus. 
*Pileopsis vetusta. 
*P. tubifer. 
^Phillipsia gemmulifera. 
*P. quadriserialis. 
• The fossils marked with an asterisk were not found in the lime¬ 
stone above the dolomite, and appear to indicate a shallower sea than 
that which subsequently existed. 
We may suppose that the depth of the water, during the deposi¬ 
tion of these beds of flaggy limestone and calcareous sandstone, was 
greater than during the period of the plant beds, or Old Red con¬ 
glomerate ; but the presence of such fossils as Trilobites, Modiola, 
