24 Proceedings of the Royal Physical Society. 



lava. While reflecting on the history of these ancient strata, 

 one cannot avoid asking the question — whence came these 

 fragments of sedimentary and volcanic rocks that belong to a 

 period intervening between the Archaean gneiss and the 

 deposition of the basement beds of the Cambrian strata ? 

 And yet they plainly indicate that during that long cycle of 

 time — which may be as long, or even longer, than that ex- 

 tending from the Cambrian period to the age in which we 

 live — the same geological agencies were in operation. It 

 cannot be doubted that, during the deposition of the strata 

 from which the Cambrian pebbles were derived, forms of life 

 of some sort must have flourished on the earth. It becomes, 

 therefore, a matter of absorbing interest to search for relics 

 of these strata which may throw light on this vast interval 

 of time. Surely they may yet be met with, not converted 

 into schists ; indeed, there is every reason to hope that some 

 traveller may light on them in some remote part of the globe 

 like that described by Eichthofen, where a rich fauna may 

 be exhumed from strata older than those now known as the 

 Primordial Zone. When studying palaeontology at the School 

 of Mines under my revered teacher Salter, I well remember how 

 he spoke of his eager search in the Longmynd strata for fossils 

 older than those of the Lingula flags. I could not then under- 

 stand how the discovery of such a fossil as Palaeopyge Ramsayi 

 should have aroused within him a keen desire to know more 

 of the fossils that were probably contained in these old 

 Welsh rocks. But my experience since that time enables 

 me to sympathise with that irresistible longing to add to our 

 knowledge of the earliest forms of life on the globe, and 

 I can quite realise the feelings which Dr Hicks must 

 have experienced when he unearthed from these strata such 

 an abundant fauna. It can hardly be maintained that these 

 organic remains represent the earliest appearance of life on 

 the globe, for all the great divisions of the invertebrata even 

 then existed, thus implying a vast amount of specialisation 

 and differentiation. We can scarcely expect that our own 

 rocks will yield much fresh light regarding an older fauna, 

 but we may cherish the hope that this hidden treasure awaits 

 the investio'ator in other lands. 



