556 J. Pringle — Loicer Tremadoc Rocks, St. David's. 



Tubes without extraneous building material and with a cancellar 

 ornament are also found in the Cretaceous rocks of England, and 

 some were referred to Terebella lewesiensis by Davies. All those from 

 the Chalk are here separated as ' Terebella' cancellata, n.sp. (Figs. 3-5). 



Two tubes made of mud bricks are discussed. One, apparently of 

 Lower Cenomanian age, is referred to the rather doubtful genus 

 Keclcia (Fig. 1). The other, from the Gault, is referred to Granidaria 

 (Fig. 2). Both these genera are held to be of Annelid origin. 



IV. — Note on the 'Lower Tremadoc' Rocks of St. David's, 

 Pembrokeshire. ' 



By John Pringle. 



IN the year 1866 Hicks and Salter recorded 2 the occurrence of 

 certain rocks in the neighbourhood of St. David's which they 

 regarded as Tremadoc deposits. The beds appeared to them to rest 

 conformably on the Lingula Flags, but when the rocks were compared 

 with those of the Tremadoc area striking lithological diffei'ences 

 were noticed. Accompanying the report was a list of fossils collected 

 from the beds, and the fauna was so wholly unlike that of the 

 North Wales deposits that the authors were led to conclude that 

 the dissimilarity was due to the conditions under which the strata 

 were deposited. 



In 1873 the group was again described by Hicks. 3 In this paper 

 and in a later one 4 the author gave an account of the lithological 

 characters of the rocks, their relation to other formations, and their 

 distribution in the area, describing in his earlier contribution 3 many 

 fossil forms which he regarded as new. Despite the somewhat 

 unsatisfactory conclusions recorded in his joint paper with Salter, 

 Hicks expressed his conviction in the two papers that the strata 

 were Lower Tremadoc. 



Since the publication of the last-mentioned memoir, and especially 

 in the light of evidence collected elsewhere, doubts have arisen as 

 to the correctness of Hicks' views. With a hope of clearing up the 

 question of age, the writer was instructed to collect from the group 

 where it is best exposed in the St. David's district, namely, on 

 Ramsey Island and on the mainland at the north end of Whitesand Bay. 



Ramses' Island. 



The ' Lower Tremadoc ' rocks occupy a small area in the north- 

 east corner of Ramsey Island. They form a narrow strip between 

 Ogof Velvet and Bay Ogof Hen (see Sketch - map). They 

 extend for a short distance southwards, but are cut out by a fault 



1 Communicated by permission of the Director of H.M. Geological Survey. 



2 Hicks & Salter, Second Eeport on the Menevian Group and other 

 formations at St. David's, Pembrokeshire: Eep. Brit. Assoc, Nottingham, 

 1866, p. 184. 



3 H. Hicks, "On the Tremadoc Bocks in the neighbourhood of St. David's, 

 South Wales, and their fossil contents " : Q.J.G.S., vol. xxix, p. 39, 1873. 



4 H. Hicks, "On the Succession of the Ancient Bocks of St. David's" : 

 Q.J.G.S., vol. xxxi, p. 167, 1875. 



