Geological Society of London. 379 
beds and constitute an order of succession in a considerable number of 
the sections. All three divisions, however, may be regarded as com- 
posing one great group, forming a great primary synclinal, with sub- 
ordinate anticlinal folds along N. and 8. lines. The relation of these 
beds to the Denbighshire Grits and Tarannon Shales has been in- 
vestigated in neighbouring districts. The author regards the Plyn- 
limmon Grits as representing a special gritty development in the 
Tarannon Shales, and so above the Llandovery Grits. The Metalli- 
ferous Slates and the Aberystwith Grits, an arenaceous development 
of their lower parts, represent the Llandovery group of the Survey, 
probably the Upper and a part of the Lower Llandovery. There does 
not appear to be any evidence of a break in this district between the 
Upper and Lower Silurian. This is confirmed by paleontological 
evidence, and in the study of the Graptolites the author has been 
assisted by Mr. Lapworth. These show that the Mid-Wales beds are 
on the horizon of the Upper Birkhill group of Scotland, and of the 
Coniston Mud-stones of the Lake-district. A table of fossils was 
appended to the paper, with a description of some new forms. The 
Appendix, by C. Lapworth, LEsq., described a new species of 
Cladophora. 
5. ‘On new Erian (Devonian) Plants.” By J. W. Dawson, LL.D., 
F.R.S., F.G.S. 
The paper first referred to recent publications bearing on the Erian 
(Devonian) flora of N.E. America, and then proceeded to describe new 
species from New York and New Brunswick, and to notice others from 
Queensland, Australia, and Scotland. 
The first and most interesting is a small Tree-fern, -Asteropteris 
noveboracensis, characterized by an axial cylinder composed of radiating 
vertical plates of scalariform tissue, imbedded in parenchyma, and 
surrounded by an outer cylinder penetrated with leaf-bundles with 
dumbbell-shaped vascular centres. The specimen was collected by Mr. 
B. Wright, in the Upper Devonian of New York. 
Another new fern from New York is a species of Hyuwisetites (£. 
Wrightianum), showing a hairy or bristly surface, and sheaths of about 
twelve, short, acuminate leaves. 
A new and peculiar form of wood, obtained by Prof. Clarke, of 
Amherst College, Massachusetts, from the Devonian of New York, 
was described under the name Celluloxylon primevum. It presents 
some analogies with Prototaxites and with Aphyllum paradocum of 
Unger. 
Several new ferns were described from the well-known Middle 
Devonian plant-beds of St. John’s, New Brunswick; and new facts 
were mentioned as confirmatory of the age assigned to these beds, as 
showing the harmony of their flora with that of the Krian of New 
York, and as illustrating the fact that the flora of the Middle and» 
Upper Devonian was eminently distinguished by the number and variety 
of its species of ferns, both herbaceous and arborescent. It will pro- 
bably be found eventually that in ferns, equisetaceous plants, and 
conifers, the Devonian was relatively richer than the Carboniferous. 
Reference was also made to a seed of the genus Atheotesta of 
Charles Brongniart, found by the Rev. ‘I. Broun in the Old Red 
