242 THE OLENELLUS ZONE IN THE NOETH-WEST HIGHLANDS. 



and JSalterella, and their associated occurrence seemed to prove most 

 conclusively the Lower Cambrian age of these rocks. Great stress 

 had been laid by Mr. Peach on the non-detection of the facial suture 

 in Olenellus, as proving that the Olenelli had no free-cheeks, and 

 should therefore be separated from the Trilobita. But in Cono- 

 coryj)he and many other trilobites the facial suture was often 

 obscure, nevertheless he saw no reason to doubt its existence in all 

 the group — only in some trilobites it was more visible than in 

 others ; nor did he see any grounds whatever fpr separating the 

 Olenelli from the Trilobita, as ancestral forms of Limuli, more than 

 any other members of the order, with which they certainly agreed 

 in all their general characters. 



The Peesident spoke of the detailed and accurate field-work on 

 which the paper was based. There could now no longer be any 

 question as to the pre-Cambrian age of the Torridon Sandstone, 

 which might for the sake of brevity be termed Torridonian, until its 

 true place in the geological record was fixed. He objected to the 

 Torridon Sandstone being classed as Archaean, and remarked that 

 already the officers of the Geological Survey had detected traces of 

 organic remains in it, and by further investigation other and better- 

 preserved forms might be obtained. With regard to the discovery 

 of the Olenellus-zone, he believed that we were only at the threshold 

 of what was yet to be found. It was intended to prosecute a 

 vigorous search along the outcrops of the strata this summer, and he 

 hoped that before long they would have further results to communi- 

 cate to the Society regarding these early portions of the Palaeozoic 

 rocks. 



Prof. Lapwokth also spoke. 



Mr. Peach replied to the remarks made by previous speakers. 



