[ 246 ] 



IX. 



PRELIMINAEY NOTICE OF SOME NEW FOSSILS FEOM 

 BEAY HEAD, COUNTY WICKLOW. 



By Eev. W. J. EYAN, S.J., and T. HALLISSY, B.A., M.E.I.A. 



Plates XXII-XXIV. 



Read February 12. Published March 8, 1912. 



The object of the present preliminary paper is to call attention to the 

 discovery, in the formation known as the Bray and Howth series, of fossil 

 organic remains, constituting new records for this formation, and representing 

 species possibly new to science. 



Considerable difference of opinion has hitherto existed among geologists 

 with regard to the stratigraphical position of the Bray and Howth rocks in 

 the geological series. The older geologists, including Professor J. Beete Jukes, 

 referred them to the Cambrian system, basing their conclusion mainly on the 

 supposed existence of an unconformity between these rocks and the Silurian 

 beds with which they are in contact. Some former officers of the Geological 

 Survey — notably Mr. A. McHenry — on the other hand, deny that such an 

 unconformity exists, and regard the Bray and Howth rocks as of Upper 

 Silurian age. In the Geological Survey Memoir to accompany Sheet 112 (Drift 

 series), Mr. G. W. Lamplugh questions even the Lower Silurian age of the 

 altered slates adjoining the granite in Sheet 112, and calls attention to the 

 similarity in character of the so-called Cambrian and Lower Silurian rocks of 

 the east of Ireland to the Skiddaw Slate series of the l^ake district and to the 

 Manx series of the Isle of Man ; he thinks it highly probable that these may 

 all form detached portions of the same ancient rock-group.' Although the 

 general consensus of opinion inclines to the views of the earlier observers, it 

 has been impossible, in the absence of well-recognized type-fossils from the 

 supposed Cambrian formation, and because of the obscurity of the strati- 

 graphical field-relations of the rocks of the district, to settle the question 

 definitely. Hence the additional fossil evidence which we now bring to bear on 



1 Geol. Survey Memoir to accompany Sheet 112 (Drift Series), p. 8. 



