I1V.—The Glacial Deposits of Northern Pembrokeshire. By T. J. Jehu, M.D. (Edin.), 
M.A. (Camb.), F.G.S., Lecturer in Geology at the University of St Andrews. 
Communicated by Professor James Gerkig, LL.D., F.R.S. (With a Plate.) 
(Read February 15, 1904. Issued separately April 9, 1904.) 
CONTENTS. 
PAGE PAGE 
I, INTRODUCTION ; ‘ ; : 5 = 1B IV. DEscRIPTION OF THE DEPOSITS . Z 5 (a3) 
1. The Lower Boulder-Olay  . ; . 63. 
II. Previous LITERATURE . ‘ ‘ , _ aye! 2. The Sands and Gravels é 3 68 
3. The Upper Boulder-Clay and Rubbly- 
Drift : : : : : ; 
III. Puystcan FEATURES AND GEOLOGY OF THE 
V. THE BovuLDERS AND ERRATICS , A Eeimee (ti 
DistRIcT «lk : : . . - 56) VI. Genera Concuusions . ‘ F : ase: 
J. INTRODUCTION. 
The area embraced in this paper consists of that part of Pembrokeshire which 
lies to the north and north-east of St Bride’s Bay. Bounded on the west by St 
George’s Channel and on the north by Cardigan Bay, it extends to the north-east as 
far as the mouth of the river Teifi, near Cardigan. 
That part of the country which lies in the immediate neighbourhood of St David's 
has, through the laborious researches of the late Dr Hicks and others, become well- 
known to geologists, and may now be regarded as classic ground. The solid geology 
of this promontory has given rise to much discussion, and has, perhaps, attracted more 
attention than that of any other part of the Principality. The reason for this great 
interest is to be sought in the facts that the rocks of this area are of a very great. 
antiquity, and that the sedimentary series contain the remains of some of the earliest 
organic forms yet found in the earth’s crust, whilst the igneous rocks are also displayed 
in great abundance and variety, and present us, in the words of Sir ARCHIBALD 
GEIKIE, with “the oldest well-preserved record of volcanic action in Britain.” 
The geology of the district lying immediately to the north-east of the St David’s 
promontory has not been the subject of so much attention, but the investigations 
earried on by DE La Brcue and the other officers of the Geological Survey before the 
middle of last century have recently to some extent been revised by Mr Cowper Resp, 
and his results are published in a paper entitled “The Geology of the Country around 
Fishguard,” which appeared in the Quart. Journ. Geol. Soc. (vol. li., 1895, p. 149). 
But while so much has been written concerning the ancient rocks of this country, 
very little attention has been paid to the more recent geological deposits. Owing to 
TRANS. ROY. SOC. EDIN., VOL. XLI. PART I. (NO. 4). 10 
