190 Proceedings oftlie Royal Physical Society. 



travel, the institution of Government surveys by the differ- 

 ent nations of Europe, the States of America, and our wide 

 colonial possessions, are every year adding immensely to our 

 geological stores ; while every new addition enables us to 

 arrive at sounder conclusions than could be derived from the 

 limited data supplied by our own little islands. But while 

 all this is satisfactory for the present, and encouraging for 

 the future, there are still many points requiring immediate 

 and careful consideration, and to some of these I would now 

 direct the attention of our Society. . 



Fundamental Strata. — Premising that all demonstrable 

 geology commences with the oldest stratified rocks, the 

 question naturally occurs, Where and what are these oldest 

 strata ? We have traced life down to the Cambrian grits 

 and slates, but beyond these lie the more crystallised gneiss, 

 quartz rocks, and granitoid schists of the Northern Hebrides. 

 Shall we, with Sir Roderick Murchison, designate these the 

 " fundamental gneiss/' and seeking their equivalent in the 

 Laurentian schists of Sir William Logan, regard them as the 

 earliest and oldest of our stratified system ? Even in these 

 Laurentian strata, metamorphosed and crystalline as they 

 are, Sir William Logan and his assistants, and more recently 

 Principal Dawson, have detected traces of lowly organisa- 

 tion,* and in some portions more metamorphosed than 

 others, more traces may yet be discovered. Time was, and 

 that within the memory of most of us, when the lower 

 Cambrians were considered as azoic ; but now that life has 

 been carried downward into an older and deeper system, 

 true philosophy requires that we discard in the meantime all 

 ideas of "fundamental rocks" and " primordial zones," and 

 leave the beginning of our stratified systems, like the origin 

 of life, an undetermined, though not a hopelessly determin- 

 able problem. We may admit into our tabulations the 

 Cambrian and Laurentian as well-defined and fossiliferous 

 systems ; but dealing with rocks so metamorphosed and 



* A foraminiferal organism, Eozoon Canadense, occurring among the ser- 

 pentinous limestones in large sessile patches, after the manner of Carpenteria 

 and Polytrema. The same organism has been more recently detected in the 

 Connemara marbles of Ireland. 



