LOWER PALEOZOIC EOCKS OF HAVEKFOEDWEST. 485 



' The last appearance of the conglomerate eastward, in the area we 

 have examined, is in a quarry west of Wheelabout, where it is 

 succeeded by sandstone, the beds dipping N.W. It occurs at this 

 place also above beds of the Slade stage, which are well seen at the 

 " k " of " Bank Saison " dipping west. 



Prom the numerous exposures of the beds of this series, where 

 they immediately succeed the Slade beds, there seems little doubt 

 that this is the true position of the conglomerate ; and as we have 

 found no evidence of its resting upon any beds lower in the series, 

 it would seem that there is no very great physical discordance at 

 the base of the conglomerate-band, which nevertheless may marlc 

 an important physical change in the area. 



We have unfortunately been unable to find any exposures showing 

 the conglomerate succeeded, without suspicion of faulting, by still 

 higher beds, • as it occurs in most cases on the summits of ridges, 

 and the higher strata have been removed by denudation. In one 

 instance, however, the grit is found between the Bala and the 

 fossiliferous Lower Llandovery beds. This is in a section, pre- 

 viously alluded to, on the railway between Haverfordwest station 

 and Sholeshook. The diagram section (fig. 5) shows the actual 

 exposures, and the fault and folds which we consider necessary to 

 explain the apparent sequence. Between the Sholeshook limestone 

 and the grit only one isolated exposure is seen, in a lane east of the 

 railway, having beds lithologically like those of the Slade stage, and 

 containing fossils which are too imperfect for determination. The 

 beds between the grit and the station are also somewhat un- 

 fossiliferous, and though the fossils found, including FJiacojjs mv- 

 cronatus, Ang. (the form which occurs in the Upper Brachiopod beds 

 of Sweden, and not the variety of the Sholeshook and Eedhill beds), 

 seem to indicate the Lower Llandovery age of the beds, the deter- 

 mination is doubtful. "We can, however, draw no line between 

 these beds and the very fossiliferous beds of the Gas-works, of true 

 Lower Llandovery age. 



Another point to be noticed is the absence of the conglomerate, 

 which, however, occurs in connexion with the grit, further east, as 

 above described. Its absence appears to point to the existence of a 

 fault, as well as the inversion represented in the diagram. The 

 relationship of the conglomerate series to the Lower Llandovery 

 further east is obscure, owing to the paucity of sections. Prom the 

 nature of the ground, we should expect this series to pass con- 

 tinuously round from Wiston to Slebech, thus lying between the 

 Lower Llandovery and the Bala beds which occur further east. 



What scanty evidence we have, therefore, certainly points to the 

 conglomerate series being immediately succeeded by the fossiliferous 

 Lower Llandovery beds, and this conclusion is supported by the 

 palseontological evidence ; for the fauna of the Slade beds, thougli 

 difiering from that of the Lower Llandovery beds, has several forms 

 in common. 



Moreover, the accumulation of the conglomerate series shows 

 only a slight pause in a period during which beds of similar litho- 



Q.J.G.S. No. 163. 2 1 



