i . OLENELLTJS ZONE IN THE NORTH-WEST HIGHLANDS. 241 



rig. 9. 0. Lapworthi. — ? First or second body-segment, nat. size. ' Fucoid Beds,' 



Allt Eigh Ian. 

 Fig. 10. 0. Lapworthi. — ? Third body-segment, nat. size. ' Serpulite Grit,' near 



Loch an Nid. 

 Fig; 11. 0. Lapworthi. — Fragment of telsou, nat. size. ' Fucoid Beds/ Allt Eigh 



Ian. M 2479«>. 

 Fig. 11 a. Counterpart of fig. 11. 

 Fig. 12. Olenelliis, sp. — Fragment of cara,pace, nat. size. ' Fucoid Beds,' Allt 



Eigh Ian. 

 Fig. 12 a. Counterpart of fig. 12. 



Fig. 12 h. Ornamentation from margin of fig. 12, magnified. 

 Fig. 13. Olenellus, sp. — Fragment of carapace, nat. size. Conjectural restored 



outline to show probable position of part preserved. ' Fucoid Beds,' 



Allt Eigh Ian. 



The numbers M 2473^, etc., refer to the List-books of the Geological Survey 

 of Scotland. 



Discussion. 



Dr. Hicks was much pleased to find that the interpretation of 

 the succession in the older rocks of Scotland now given by the 

 Authors agreed entirely with the views which he had advocated for 

 so many years, not only as applicable to Wales, but generally to 

 the British Isles, and to most of the continent of Europe. In a 

 map of Europe published in the Quart. Journ. Geol. Soc. in 1875, 

 he indicated by sections the varying thicknesses of the deposits in 

 the different countries, and the order of the succession of the faunas, 

 and he pointed out that wherever the base-line of the Cambrian 

 rocks was seen, it was found to rest unconformably on pre-Cambrian 

 rocks. He had found fragments of Olenellus at St. David's in the 

 year 1868, but had only recently recognized that they were portions 

 of the carapace of that genus. Along with the Olenellus at St. 

 David's there appears to be a species of Conocoryplie. The latter 

 genus as now defined has, like Olenellus^ no true facial sutures, but 

 it ranges also into the Middle Cambrian, and is there associated 

 with the genus Paradoxides. jSFow that the Torridon Sandstone is 

 recognized to be of pre-Cambrian age, it is a matter of much im- 

 portance to find out the nature of the fragments contained in it, as 

 by that means it may be possible to arrive at some idea as to the 

 composition of the still earlier pre-Cambrian formations. He had 

 already tabulated a considerable number ; but doubtless there were 

 many others which he had not met with. He congratulated the 

 Authors and the officers of the Survey associated with them on the 

 important results of their labours, and he hoped they would soon be 

 able to add to their discoveries by finding other faunas. 



Dr. WooDWAKD congratulated the Authors on their admirable 

 paper. The discovery ol Olenellus in Scotland fixed with certainty 

 the Lower Cambrian age of the ' Serpulite Grits ' and ' Eucoid Eeds.' 

 He pointed out that Mr. Walcott denies the presence of Olenellus in 

 Australia, but in 1886 Mr. Hardman had sent home the head and 

 spine of a trilobite, and numerous pteropods, from Kimberley, 

 Western Australia ; these had been identified by Messrs. K. 

 Etheridge, Jr., A. H. Eoord, and Dr. Woodward as Olenellus (2) 



