4 14 Geological Society : — 



British Columbia. It consists of an almost even plane sloping at a 

 moderate or high angle, and cut at intervals by small ravines or 

 channels. The sides of the Great Glen have been planed by glacier- 

 action to a greater extent than usual, and between Loch Lochy and 

 Loch Oich, near Laggan, the sides of the Glen have a regular and 

 flat slope of over 35° up to about 1000 feet above sea-level. Numerous 

 stream-cut channels draining down this slope are, on an average, not 

 more than 10 to 15 feet deep, but some quite exceptional examples 

 may be 50 feet deep ; these channels occupy less than a fourth of 

 the surface. In addition there are larger glens which, although 

 they run out into shallow ravines where they cut the sloping side 

 of the Great Glen, are frequently 500 feet in depth among the 

 hills. If these were ordinary stream-valleys before the Glacial 

 Period, the cutting away of the ridges separating them to the extent 

 of at least 250 or 300 feet must be attributed to glacial erosion on 

 the sides of the Great Glen. The erosion of the small ravines in 

 the glacial slope must have been effected by streams in post-Glacial 

 times, and the measurement of their rate of erosion might be 

 expected to throw light on the amount of time which has elapsed 

 since the Glacial Period in this district. ' The general effect pro- 

 duced by the whole evidence is ... . the small amount of denudation 

 that has taken place since the Great Ice Age, and the necessary 

 deduction that no great period of time, measured in years, can have 

 elapsed between the Glacial Epoch and the present day.' 



2. ' On the Geology of Northern Anglesey : Part II.' By 

 C. A. Matley, Esq., B.Sc, F.G.S. 



The present paper deals in the first place with the stratigraphy of 

 the Northern Complex. The following table shows the succession of 

 the rocks in descending order : — 



C. Tue Llaxdeilo Strata. p> ee t 



Cd. Black argillaceous shales 40, top not seen. 



Cc. Irons tone, in part oolitic 20 



Cb. Grey quartzose shales or slates, striped by thin, 



black laminae 150 



Ca. 2. Pale conglomerates and grits . , 500 



1. Ped-purple conglomerate . ,- -«, 180 



B. The Llaxbadrig Series, about 1000_ feet or 1500 ; ^apparent 

 order : — 

 Bf. Quartzite. 

 Be. Pebbly slates. 



Bd. Slates with grit-and-quartzite bands. 



Be. Quartzites, shales, and some limestone (Porth Padrig. etc.). 

 Bb. Limestone (as at Trwyn y Pare). 

 Ba. Grits and slates, usually smashed to a cmsh-conglomei'ate. 



A. The Greek Series. 



Greenish and bluish slates (of the Northern Complex). 



The rocks strike east-south-east, and dip usually at a high angle 

 northward ; a well-marked transverse fault divides the complex 

 into western and eastern portions. The Llandeilo rocks occupy 



