20 MR. PHILIP LAKE ON THE DENBIGHSHIEE [Feb. 1 89 5, 



Dinas Bran Beds. 



Although they do not occur in our area, it may he well, in order 

 to complete the account of the succession in the Llaagollen basin, to- 

 give a list of the fossils which have been found on Dinas Bran. 

 The beds which occur there are more sandy than the rest of the 

 series, and break up into irregular prisms. The following list is 

 drawn from Mr. Marr's paper, with a few additions : — 



Cucullella coarctata, Phill. 

 Ctenodonta. 



Bpongarium Edwardsi, Murcli. 

 Serpulites dispar, Salt. 

 Fa vosites fibrosus, Go! df . 

 ' Actinocrinus ' pulcher, M'Coy. 

 Ceratiocaris stygia, Salter. 

 CJwnetes minima, Sow. 1 

 Dayia navicida, Sow. 

 Bhynchonella nucida, Sow. 

 Ambonychia acutieostata, M'Coy. 



Bellerophon expanms, Sow. 1 

 Theca Forbesi, Sharpe. 

 Holopella gracilior, M'Coy. 

 Orthoceras Sedgivicki, Forbes. '- 



laqueafitm, Hall. 



ibex, Sow. 



Calymene. 



VI. Correlation with other Areas. 

 Vale of Clwyd. 3 



The lower part of the Denbighshire series in the Clwyd valley 

 corresponds so exactly with that in the Vale of Llangollen that the 

 same description will apply to both, and it is quite unnecessary here- 

 to enter into further details. It is in the upper part of the series 

 only that no precise correlation can be attempted. Acidaspis 

 Hughesi has not been found in the Dee Valley ; and on the other 

 hand the zone of Monograptus leintwardinensis is unknown in the 

 Vale of Clwyd, nor does it appear — since the Llansannan Shales are 

 not to be correlated with them — that anything precisely correspond- 

 ing with the Dinas Bran Beds has yet been recognized in North 

 Denbighshire. These points require further examination ; for at 

 least there can be little doubt that both Acidaspis Hugliesi and 

 Monograptus leintwardinensis will be found to occur in both areas* 



The Long Mountain. 



Outside of Denbighshire itself, the region which resembles the- 

 Vale of Llangollen most closely in its geology is the Long Moun- 

 tain, which has been briefly described by Mr. Watts. 4 The sequence 

 which he establishes corresponds very precisely with that in our 

 area. Above the May Hill Grit come purple and green shales with 

 few fossils, which agree on the whole with the grey slates and 

 greenish Tarannon Shales which overlie the Corwen Grit in South 

 Denbighshire. They appear, however, to extend somewhat higher 

 up the series, for the succeeding ' Wenlock mudstones ' contain 

 Cyrtograptus Linnarssoni, Monograptus Flemingi, M. dubius, etc., 



1 These specimens were collected by Miss Crosfield and Miss Elles, of 

 Newnham College, Cambridge, and are now in the Woodwardian Museum. 



2 This is the Orthoceras tenuicinctum, Portl.. of M'Coy's (Brit. Pal. Foss, 

 p. 359) and Marr's lists. 



3 Hughes, Proc. Chester Soc. Nat. Sci. & Lit. pt. iv. (1893) p. 141. 



4 Eep. Brit. Assoc. (Leeds), 1890, p. 817. 



