b PROCEEDINGS OF THE CANADIAN INSTITUTE. 



Stone, and lie beneath the Olenellus Zone (the so-called base of the Cambrian). 

 In the pre-Cambrian rocks of Wales and elsewhere fossils have been found, but not 

 of a more satisfactory character than those already mentioned. I do not here 

 discuss the so-caUed fossils of the Huronian and Laurentian, because until the 

 vast beds of the Keweenawan and Animikie are cleared up it is hardly worth 

 while to enter upon a mere controversy as to whether certain forms are fossils 

 or not. 



The subject is complicated by the many breaks or unconformities in Cambrian 

 and pre-Cambrian times. In the extended areas of ancient rocks in North 

 America there are sections where the Lower or some younger portion of the Cam- 

 brian rests directly upon Archaean or other pre-Cambrian rocks, and there are 

 plades where the section is conformaible from the Cambrian series downward for 

 many thousands of feet into the Keweenawan. Therefore, considering the many 

 widely separated sections in North America, if at any point downward we were 

 ^ble to say we had reached the stage where in North America the Palaeozoic rocks 

 ended, it would seem at first sight as if we might conclude that the fossil remains 

 found at this- base, represented the beginning at least or organisms having hard 

 parts. But presuming that the labours of Matthew, Walcott, and others eventually 

 •tarry the Paheozoic record through the Keweenawan, down to the lowest of the 

 beds of the Animikie, which " except when of volcanic origin," resemble " in 

 their laspect the older Palfeozoic sediments," we are then met, ait least in the areas 

 which Dr. Dawson has so happily called the " continental Protaxis of the North," 

 with a gap in the record which he describes in the address from which I have 

 already quoted, as " the vast lapse of time, constituting probably one of the most 

 important breaks in geological history, by which the Cambrian and its allied rocks 

 are separated from those of the Huronian and Laurentian systems." Regarding 

 this break. Dr. Dawson says: " It would be difficult to deny that the time thus 

 occupied may not have been equal in duration to that represented by the whole 

 o{ the Palaeozoic." 



In the scattered and unsatisfactory fragments referred to above it cannot be said 

 that we have found a fauna essentially different from the Cambrian, but somewhere — 

 it may be in North America, in the Salt Range of India, in the Torridon sand- 

 stones of Scotland which are pre-Cambrian and said to be 10,000 feet in thick- 

 ness, in Bohemia or Wales — we will doubtless be able to carry the history of the 

 highly-developed trilobites and other organisms of the Cambrian at least further 

 back towards their origin. This is the undiscovered shoreline in geology. In 

 quest of it the Nansens of geology will travel as long as the limits of discovery 

 are unsolved. We must not, however, forget that animals without hard parts 

 leave no, or nearly no, record, and that the progenitors of many animals with hard 

 parts had themselves no hard parts. In this co-nnection Professor Marr.^i) after 

 discussing the peculiarities of a well-known Cambrian trilobite, says: " If this 

 be so, the entire outer covering of the trilobites, at a period not very remote from 

 the end of pre-Cambrian times, may have been membranous, and the same thing 

 may have occurred with the structures analogous to the hard parts of organisms 

 of other groups. Indeed, with our present views as to development, we can 

 scarcely suppose that organisms acquired hard parts at a very early period of 

 their existence, and fauna after fauna may have occupied the globe, and disap- 

 peared, leaving no trace of its existence." 



I have thus far been considering the value of fossils in demonstrating the 

 position and relative age of the different strata of the earth's crust. It is not 

 necessary for such purposes that the fauna of one stratum should bear any like- 

 ness to that of an immediately older or younger stratum. Indeed, to some extent, 



(i) J. E. Marr. Presidential Address, Geological Section, B.A.A.S., 1896. 



