Br. H. Woodward — A New Gault Crustacean. 61 



rest of its course tlieve is no evidence of the existence of glacial 

 drift; but on the contrary some evidence that there is no drift in 

 the depression, for solid rock is seen close to the stream at 100 yards 

 north of the narrow-gauge railway ; and still further north the 

 valley is cumbered with large angular blocks consisting entirely 

 of diabase, which have fallen from the cliffs above. There is no 

 drift, for were there any we should find stones of many different 

 sorts, and many of them would be rounded. So Mr. Marr's drift- 

 filled gorge 350 feet deep is a mere figment of the imagination. 

 I must also remark that judging from the shape of the ground Llyn 

 Cwellyn is probably a great deal more than 50 feet deep. 



As to the- peaty watershed near Pitts Head, it matters nothing 

 whether it is "composed of an alluvial deposit " or not, for the solid 

 rock comes to the day in so many places that the superficial 

 covering is evidently merely a thin skin. 



On the next page the authors say " the bed of the Colwyn runs 

 over drift until within a short distance of Beddgelert." I am sorry 

 to be obliged to contradict the writers, but the above statement 

 is incorrect. Neither the Colwyn nor its bed runs over drift 

 immediately south of Pitts Head watershed, for solid rock is seen 

 in the bed of the river at Pont Caer-gors and at several other 

 places for more than 550 yards down-stream, at which distance 

 the river actually runs in a rocky gorge. The eastern side of 

 the Colwyn valley is formed of solid rock, not only throughout 

 the whole of this distance, but for much further south. A low 

 bank of drift forms the western margin of the river immediately 

 south of Pont Caer-gors. This drift obviously lies as a tablecloth 

 on a gently sloping surface of rock which comes to the day 300 

 yards west of the bridge. No drift-buried gorge is possible here. 

 The upshot is that Messrs. Marr and Adie, in their hurry to escape 

 from a rock basin, have invented an impossible gorge to carry the 

 water of Llyn Cwellyn across a mountain range whose lowest point 

 is 650 feet above the sea, tliat is, 186 feet above the present level 

 of the lake. This is a brilliant effort of the imagination, though 

 hardly of the scientific sort, but it does not come near that of the 

 old Welsh, who imagined an underground connection between Llyn 

 Cwellyn and the Llanberis lakes to account for the existence of char 

 in both. 



IV. — Note on a Crustacean Mesodromilites Birleti, gen. et 

 sp. NOV., from the Gault of Folkestone, Kent. 



By Henut Woodward, LL.D., F.R.S., F.G.S., etc. 



ONE of the results incidental to the meeting of the British 

 Association for the Advancement of Science at Dover in 

 September last was a visit paid to Folkestone by the members of 

 Section C (Geology). Among the ladies present was Miss Caroline 

 Birley, well known both as a traveller and for the deep interest 

 which she has always taken in palfBontological research ; she is also 

 the owner of an excellent private museum of minerals and fossils. 



