Kin ah an — On Oldhamia. 341 



the Bray Head Cambrians. In these no Oldhamia has been 

 found, although we searched them very carefully ; nor is there any 

 intrude of Quartz-rock. 



In Howth promontory, Co. Dublin, Wyley classed the rocks as 

 ■Cambrians, while subsequently J. E. Kinahan found at Puck 

 Eock Oldhamia antiqua. (?) The specimens I found in this 

 locality were on a smooth pale-green phylitic shale. I do not 

 think there is an intrude of Quartz-rock in connection with this 

 special locality ; but elsewhere in Howth there are different in- 

 trudes of Quartz-rock, and in connection with them there are not 

 any known localities for Oldhamia. 



At Bray Head, Co. Wicklow, Oldhamia (radiata and antiqua) 

 occur in numerous places. Those with which I am the more inti- 

 mately acquainted are more or less in connection with the intrudes 

 of Quartz-rock ; some places, however, are not so. 



At Grreystones, south of Bray Head, Oldhamia has also been 

 found ; but my knowledge of these rocks is too scant to mention 

 more about them. According to the map in this neighbourhood 

 there are intrudes of Quartz-rock. 



In Carrick Mountain, south of Grlenealy, is the locality where 

 Oldhamia was first found by Flanagan. Here it occurs as 0. 

 radiata, 0. antiqua, and 0. cliscreta, the latter being an intermediate 

 form between the others, to which attention was first drawn by 

 J. E. Kinahan (Trans., Eoyal Irish Academy, vol. xxiii., p. 547). 



At Flanagan's locality the Oldhamias occur in purplish shales 

 like those of Bray Head, and in phylitic pale- greenish shales, the 

 best marked specimens being in the latter. This locality is inti- 

 mately connected with intruded cakes of Quartz-rock. 



At Eoney Eock, south of Courtown Harbour, Co. Wexford, 

 alongside an intrude of Quartz-rock, in a thin bed of red shale, 

 there is 0. antiqua. 



Farther south along the Wexford coast, at Cahore bathing- 

 place, 0. radiata occurs in a purple bed, like those of Bray Head ; 

 while at Cahore Head, 0. antiqua occurs sparingly in a light-green 

 phylitic shale. Here there are no intrudes of Quartz-rock. 



Going still further southward, to the south-east and south of 

 Bannow are other Cambrian rocks. These I have very carefully 

 examined. Along the south coast the Oldhamia was only found 

 in reddish, or slightly purplish, beds ; the three forms, 0. radiata, 



