THE 



GEOLOGICAL MAGAZINE, 



No. XXXVII.— JULY, 1867 



I. — On Traces of Glacial Action neae Llandudno. 



By the Eev. T. G. Bonney, M.A., F.G.S. 



(PLATE XII., Figs. 1 & 2.) 



ANYONE accustomed to the peculiar outlines which ancient ice- 

 action has produced in the Alps, cannot fail to be struck, at the 

 first glance, by the contours of the upper parts of the Great Ormeshead 

 and of the Carboniferous Limestone range which extends from near 

 the village of Ehos to the Little Ormeshead ; and a more minute 

 examination only strengthens the conviction that, while the leading 

 outlines of the hills are due somewhat to upheaval, but mainly to 

 denudation — probably marine, the surface of the higher ground has 

 in many cases been aifected by ice. 



The following notes were made during a brief visit to Llandudno 

 in the month of April last. They refer chiefly to (a) the Great 

 Ormeshead, (6) the Little Ormeshead, (c) the Coast section between 

 the former and Conway. The bad weather and the shortness of my 

 stay have made them less complete than I could have wished, but 

 still they may be of use in calling attention to a neighbourhood at 

 once so accessible and so interesting. 



(a) The upper part of the Great Ormeshead is an undulating 

 plateau of Carboniferous Limestone, in places almost bare of vege- 

 tation. Immediately on gaining this by the path which slopes up 

 the steep south-western face of the hill, from above the ruins of 

 Gogarth Abbey, one is struck with the general resemblance of the 

 surface to that of some of the higher limestone districts in the Alps; 

 for example, that between the Schwarenbach Inn and the Gemmi Pass. 

 Large blocks of limestone are scattered about, especially in the 

 neighbourhood of the north-western angle of the plateau. One re- 

 markably fine mass (Plate XII., Fig. 2) is about 5ft. 7in. in height 

 and 7ft. 2in. by 7ft. in breadth and thickness. It is very flat on the 

 under side, and rests upon three or four projections of the rock below. 

 Several of these blocks differ slightly in lithological character from 

 the rock on which they lie ; for they consist of a very hard kind of 

 limestone, which, when broken by the hammer, does not exhibit the 

 usual sharp and somewhat conchoidal fracture common in the Car- 



VOL. IV. NO. XXXVII. ly 



