PALAEOZOIC FOSSILS, 
143 
the common woodlouse, and examples of these rolled-up fossils 
will be found in the collection. 
The visitor is not likely to overlook the large specimens of 
Pentamerus Knightii, a characteristic brachiopod of the 
Aymestry limestone. 
Some specimens of the Ludlow and Old Red Sandstone 
Crustaceans, such as Euryptevus and Pterygotus, will be found 
in Wall Case 10 . A cast of a remarkably fine Pterygotus , from 
Scotland, showing the perfect form of this gigantic crustacean,, 
is in a glass case against the wall in Recess No. 18. 
The earliest known relics of vertebrate life in the British 
rocks occur in the Ludlow series. Even in the Lower Ludlow 
beds remains of fishes have been detected, but in the Upper 
Ludlow group they become abundant, though fragmentary.. 
Examples of these fishes, the precursors of those which abounded, 
in the Old Red Sandstone period, will be found in Wall Case 16 , 
The fossils of the Old Red Sandstone and Devonian strata 
receive ample illustration in Wall Cases 10 and 11 , as well as in 
the Flat Cases 29 to 35. The Devonian system comprises all 
the marine strata in the south-west of England between the- 
Silurian and Carboniferous systems. It is especially in the 
limestones of the Middle Devonian group, near Torquay, that 
fossils occur. The Great Devon Limestone is rich in corals, 
some of which appear to have grown in reefs, and a large suite 
of polished specimens will be found partly in the Wall Cases and 
partly in a Table Case(C), in the Recess No. 16. 
From the Old Red Sandstone, which consists of strata* 
deposited in inland waters, few fossils have been obtained, » 
excepting the remains of fishes. The remarkable fishes, pro* 
tected with bony plates and strange head-bucklers, are repre- 
sented by such forms as Cephalaspis and Pterichthys, principally 
from Scotland. Most of the Old Red Sandstone fishes belong to 
the group of ganoids, of which the bony pike of the North; 
American rivers is a good modern example. Ganoid fishes, 
though now limited to a very few species, were richly repre- 
sented in the waters of the Old Red Sandstone. Some large 
blocks of the sandstone of Dura Den, in Fife, densely crowded 
with the remains of Holoptychius, will attract the eye by the' 
contrast of the black fossils with the yellow matrix. The 
Dipterws of the Old Red Sandstone is interesting, as being allied, 
to certain amphibious fishes, capable of breathing either atmo- 
spheric air or air dissolved in water, represented at the present 
day by such gill-bearing and lung-bearing forms as the 
Ceratoclus of Queensland. As illustrating the land vegetation of 
the Old Red Sandstone period, attention should be given to the: 
fine f mnds of Palceopteris (J diantites), from Kiltorcan in 
Kilkenny, an example of which is placed near the eastern 
staircase. 
Above the Devonian and Old Red rocks come the beds 
forming the Carboniferous system, This is a great series of 
