Yol. 52.] LLANDOVERY AND ASSOCIATED BOCKS OF CONWAY. 283 



Tarannon Shales; they are generally harder, of a lighter, often 

 speckled colour, and in places very shivery. The fossils are fairly 

 well preserved, but, owing to the direction of the cleavage, are often 

 difficult to obtain. The beds change their strike somewhat as they 

 approach the faults, being in each case bent up towards them ; this 

 is especially well marked in the case of the fault which forms the 

 boundary of the Silurian rocks to the west. We were fortunate in 

 having several workable exposures on the hillside, and these we will 

 proceed to describe in some detail. 



(i.) Sections West of Fault (F. 2). 



(a) Section S.W. of Rose Mill Farm. — The sections exposed near 

 Rose Mill Farm are of small extent. They are chiefly interesting 

 as showing the alteration in the strike of the beds as these approach 

 the fault. Here the strike is 20° N. of W., while as a general rule 

 it is 10° N. of W. The fossils here are for the most part but poorly 

 preserved, but we have identified Monograptus personatus, Tullb., 

 M. vomerinus, Nich., M. broughtonensis (Nich..), and Cyrtograptus 

 Murchisoni, Carr. At Rose Mill Farm itself the shales are very 

 shivery, and from the nature of the rock no fossils were obtainable. 

 Here and south of the farm the strike is 15° N . of W. 



(/3) Neckarmount. — An exceedingly good section is exposed along 

 the rough cart-track which leads up from the road, past Neckarmount 

 House, to the farm. 



The beds appear to come on about 160 yards above Gyffin Road ; 

 they dip steadily into the hill to the S.S.W. at a high angle of 

 about 50°, and maintain a constant strike 10° N. of W. The 

 shales do not appear to be equally fossiliferous throughout. In 

 some bands graptolites are abundant, while others appear to be 

 quite unfossiliferous. The fossiliferous bands yielded Monograptus 

 priodon, Bronn, M. vomerinus, Nich., M. personatus, Tullb., M. 

 ■flexuosus, Tullb., M. Hisingeri, var. rigidus (?), Lapw., and Cyrto- 

 graptus sp. 



East of Neckarmount the harder unfossiliferous bands are exposed, 

 at the top of a sudden rise of ground. Here the direction of strike 

 changes to 20° N. of W. This is evidently due to the presence of 

 the fault (F. 2), which is at this place in close proximity. 



(ii.) Sections East of Fault (F. 2). 



(a) Road-section. — As mentioned above, the Wenlock Shales are 

 faulted against the Tarannon Shales to the west. Unfortunately 

 the beds here are so deeply weathered that fossils are exceedingly 

 rare, but the change in the character of the rocks, in addition to 

 palaeoutological evidence, enables us to affirm with some certainty 

 that the beds are of Wenlock age. The only graptolites obtainable 

 were Monograptus vomerinus, Nich. (1 specimen), 21. flexuosus, 

 Tullb. (1 specimen), and Cyrtograptus*! (1 specimen). 



