
ee. «> 
ge 
ate 
TRANSACTIONS OF THE SECTIONS. 55 
patches of magnesian limestone, in which are found some shells resembling Schizodus, 
Associated with this limestone are red sandstones, supposed to be equivalents of the 
rothe-todte-liegende, and containing vegetable remains, as Calamites, Sigillaria, &c., 
but often too obscure to determine specifically. Underlying these are soft calcareous 
shaly beds, in which are many fish remains, generally of Holoptychus, and a great 
number of Modiola, with a few other shells. 
At Ballycastle and Murlough, in the north-eastern part of Antrim, there is the regu- 
lar coal formation, from which Mr. MacAdam obtained a variety of fossil plants, but 
not differing from those,of the English coal-fields, There are associated shales in 
which a Lingula is frequently found, and there is underlying carboniferous limestone 
with the usual fossils. In the County of Down at Castle Espie, near Comber, there is 
a small patch of carboniferous limestone, remarkable for the Orthoceratites it contains, 
and several other fossils, On the County Down side of Carlingford Bay there is a 
deposit of limestone, which in all probability is the same as that which occurs near 
the town of Carlingford on the south side in the county of Louth, but the fossils have 
not yet been examined. 
No Silurian rocks have yet been discovered in Antrim or Down, but it is not 
improbable that the like may be detected on more minute examination. 
On the Subdivisions of Lepteena. By Professor M‘Coy. 
On the Structure of certain Fossil Fishes found in the Old Red Sandstone 
of the North of Scotland. By Professor M‘Coy. 
The Professor exhibited specimens and plates; among others a large species of 
Holoptychius, which he named H. Sedgwicki, showing for the first time, the form, 
number, and position of the vertical fins of that genus. He also dwelt on the ana- 
tomical structure and peculiarities in the form of the tail, and the ossification of the 
vertebral column, which had been supposed to characterize the fishes found in the more 
ancient rocks, and which had been used by some recent writers in support of the 
doctrine of ‘ Progressive Development.” He pointed out that the structure of the 
fossils which he treated of disproved these notions, and strengthened the more ordi- 
nary geologicallaws. He described the peculiarities of two new genera, which united: 
the two great groups of Saurodipteridz and Ccelacanthi. 
On the Mode of Succession of the Teeth in Cochliodus. 
By Professor M‘Coy. 
Tn this communication the fact was announced that the mountain limestone genera 
of fossil fishes called Cochliodus and Peecilodus by Agassiz, and supposed by him and 
all succeeding writers to have manifested the most intimate relation to the living 
Australian shark, called Cestracion, had really a strong horny jaw for the support of 
the teeth, and that these latter succeeded each other vertically upwards, the young 
teeth appearing under the old ones; while in the living shark alluded to there was 
no horny jaw, and the young teeth followed the old ones laterally from behind for- 
wards; so that there was no such reason, as generally supposed, for quoting the 
existence of the Cestracions in the Paleozoic rocks. The nearest analogy for the 
carboniferous fossils was the osseous genus Placodus of the Muschelkalk, though it 
differed in microscopic structure. 4 


On the Structure of the South Silurian Mountains of Scotland. 
By Professor J. Nicot, £.G.S. 
On the Occurrence of Glacier Moraines in Arran. By Prof. Nicou, F.G.S. 
Notice of the Discovery of a new Talpina? 
By C. B. Rosz, F.G.S., Swaffham, Norfolk. 
In the course of last winter, I sent some fossil fish-scales from a species of Beryx; 
met with in the chalk strata, to a‘person in London, that they might be put up as 
