138 MESSES. C. I. GARDINER & S. H. REYNOLDS [Feb. 1 898, 



The conglomerate shows signs of faulting and is covered by slates 

 and impure limestones, which, as will be seen from the map (PL IX), 

 form the whole of Heath Hill. The dip of these beds is about 

 60°-50° S.S.W. at various points of the hill. From them 

 we obtained Calymene sp. ; lUcenus sp, ? ; Hemojjleurides • sp. ; 

 Trinucleus sp. ; Tiresias sp.^ 



Just above Seal Hole, on the north side of the hill, a small plug 

 of coarse porphj-rite is seen cutting into the slates, which do not 

 appear much altered bj its intrusion. The occurrence of this rock here 

 is noted in the Survey Memoir (pp. 48, 49), where it is represented 



Fig. 2. — Conglomerate from Kiln Point. 





''ISvs:^^^ 





-^^ 



xl8. 



[The section shows a fragment of a mica-andesite on the right, and on the 

 left the matrix of the conglomerate, in which smah quartz-fragments and 

 pieces of felspar and felspathic rocks are found.] 



in the section given as a mass resting on slates and covered by 

 no deposit, and it is supposed to be a remnant of a mass which 

 ' entirely embedded the conglomerate and shales.' As, however, 

 the mass of igneous rock is entirely covered and surrounded bj' 

 slates, it appears to us to be of the nature of an intrusion. 



At Eaven's Well, on the north side of the little valley leading 

 down to Seal Hole, brown and grey slates, sometimes of a very ashy 

 nature, are seen dipping at 60° S.S.W., and the faulted junction of 



' These, and the other fossils which we obtained from the island, have been 

 identified for us by Mr. F. E. Cowper Eeed, M. A., F.G-.S. A list of fossils found 

 on Lambay Island is given in the Survey Memoir, pp. 11 & 12. 



