202 T, RUDDY ON THE CAMBRIAN AND 
river Dee, I found Graptolithus priodon in abundance, a small 
variety or species with a broad shaft and straight cells, Retiolites 
Geinitzianus, Orthoceras primevum, Orthoceras sp., a few univalyes 
and bivalves of small size, Encrinites, &c. 
This. bed, which is of considerable thickness, rises again about two 
miles up the Berwyn road, where it is found resting on the Tarannon 
shales and containing the same fossils. It varies much in character, 
for on the Berwyn road it consists of fine slates, whereas these are 
represented by hard blue shales near the river Dee. 
Although I haye examined the débris at various openings in the 
interbedded grits and shales above the Graptolite zone, I have only 
found Encrinite stems and a few fragments of small bivalves. 
Srcrion IT. (fig. 2).— Returning to the south side of the lake we 
first find a thin bed of calcareous ash (No. 9), and associated with it 
layers over six inches in thickness full of Leptena sericea. Scattered 
throughout are fine specimens of Strophomena eapansa, of which 
this seems to be the true zone. Up to the next ash-bed (No. 7) the 
same fossils are sparsely distributed. Among them we find Lingula 
ovata, but not commonly, and a small species of Ctenodonta agreeing 
with that figured as Ct. obliqua in Murchison’s ‘ Siluria’ (fifth edition, 
p. 196). 
The ash-bed No. 7 is fossiliferous, but of no particular interest. 
No. 6 is a very well-marked zone. It consists of sandy limestone 
twelve feet in thickness, effervescing with acid. This is the true 
zone of Orthis vespertilio and OQ. spiriferoides, both being equally 
abundant here and seldom found in higher beds. Here we also find 
Orthis biforata, Cyclonema, and well-preserved specimens of Nebult- 
pora lens. 
This bed is very persistent in character, for we find it again at 
Garnedd occupying the same position, and it rises again in the 
Berwyns, where it is well described by D. C. Davies in a paper on 
the Berwyn Phosphate Mine (Quart. Journ. Geol. Soc. 1875, vol. 
Xxxl. p. 357). 
In the sandy shales, No. 5, we find plenty of broken specimens of 
Trilobites, such as Calymene, Homalonotus, Cybele, Phacops, and 
Asaphus Powisit, the latter bemg common. The beds 2 and 4 are 
identical in character, being composed of coarse sand; here we find 
beautiful large specimens of Orthis calligramma; Strophomena 
depressa and a few of its variety undata; Lingula ovata frequent ; 
less commonly Modiolopsis pyrus and a small Discina-lke shell. 
Near the bed of hard crystalline limestone, where the sand is much 
charged with lime, we find numerous large specimens of Orthis 
Actonie, a few of Oonularia Sowerbyi, and layers of Stenopora 
(Favosites) fibrosa over a foot in thickness. The bed of limestone 
(No. 3) is from 18 to 20 feet in thickness, and is of a hard intract- 
able nature. In the fine shales (No. 1) immediately above the bed 
of coarse sand, the fossils suddenly cease or become very small in 
size: the only thing of interest I found was a short piece of an 
Orthoceratite with a large bead-like siphuncle, agreeing with the 
description of the Ormoceras in the Cambridge Catalogue, p. 71. We 
found but a small number of Cephalopoda and Univalyes ; but if we 
