Geological Society of London. 93 
upper part of the former is sandy, and the lower part of the latter 
frequently argillaceous. Similarly no definite lme can be drawn 
between the Upper and Lower Ypresian; but in both countries this 
series is separated from overlying beds by a well-marked line of 
erosion. So also in France the base of the Calcaire Grossier 
(Bracklesham Beds) is a pebbly greensand resting on an eroded 
surface of the Sands of the Cuise-de-la-Motte. In Belgium, in 
Whitecliff Bay, and in the Bagshot district the Upper Hocene rests 
upon an eroded surface of the Lower Hocene. Subjoined is the 
author’s proposed classification of the Kocene :— 
( ENGLAND. Brier. France (Paris Basin). 
: | a. Barton Beds. a. Wemmelian. a, Sables Moyens or Grés 
3 J de Beauchamp. 
= Saree aaa 
p b. Bracklesham Beds. Lakenian b. Upper Calcaire Grossier 
| = Upper and and 
| 6*. Middle Bagshots. Bruxellian. b*. Glauconie Grossiére. 
( | Wanting. Paniselian 
London Sands = Sands of Cuise-la- Motte. 
Lower Bagshot. Upper Ypresian. 
London Clay. Lower Ypresian. Wanting. 
; Basement or Oldhaven Sables Inférieurs of the 
= Beds. P [ Soissonnais, including 
=< | Woolwich and Read- U Tiandeni + the Marls and Sands of 
3 ing Beds. Dee eerrercut 7: | Rilly, the ‘Lignites’ and 
Sands of Bracheux. 
Lower Landenian Sands of St. Omer, Douai, 
Thanet Sands and Heersian. and La Feére. 
| Wanting. Calcaire de Mons. Strontianiferous Marl of 
L Meudon ? 
2. “On the Cambrian and Associated Rocks in North-west Caer- 
narvonshire.” By Prof. J. F. Blake, M.A., F.G.S. 
After referring to the published views of Professor Sedgwick, Sir 
A. C. Ramsay, and the Geological Survey, Professors Hughes and 
Bonney and Dr. Hicks concerning the area in question and especially 
as to the presence or absence of Precambrian rocks, the author 
gave an account of his own explorations and their results, the 
principal of which were the following. 
In the Bangor and Caernarvon area three distinct conglomerates 
had been confounded. The only one that showed distinct uncon- 
formity on the underlying rock was of Arenig (Ordovician) age. 
The rocks of the southern and central portion of the area were 
essentially of igneous origin and might be distinguished into two 
groups, the southern probably intrusive, the northern certainly 
eruptive. ‘There is no evidence to show what interval of time elapsed 
between the production of these two groups, nor which of them is 
the earlier, although the author regards it as more probable that 
the southern mass is of the earlier date and overlain by the northern 
portions. ‘The Bangor beds are derived from the denudation of the 
