764 REPORT—1896. 
knowledge, but until these are discovered the palzontological record must be 
admitted to be in a remarkably incomplete condition. In the meantime a study 
of the recent advance of our knowledge of early life is significant of the mode in 
which still earlier faunas will probably be brought to light. In 1845 Dr. E. 
Emmons described a fossil, now known to be an Olenellus, though at that time the 
earliest fauna was supposed to be one containing a much later group of organisms, 
and it was not until Nathorst and Brégger established the position of the Olenedlus 
zone that the existence of a fauna earlier than that of which Paradoxides was a 
member was admitted ; and, indeed, the Paradovides fauna itself was proved to be 
earlier than that containing Olenws, long after these two genera had been made 
familiar to paleontologists, the Swedish paleontologist, Augelin, having referred 
the Paradoatdes fauna to a period earlier than that of the one with Olenus. It is 
quite possible, therefore, that fossils are actually preserved in our museums at the 
present moment which have been extracted from rocks deposited before the period 
of formation of the Olenel/us heds, though their age has not been determined. The 
Olenellus horizon now furnishes us with a datum-line from which we can work 
backwards, and it is quite possible that the Meobolus beds of the Salt Range," 
which underlie beds holding Olenel/us, really do contain, as has been maintained, a 
fauna of date anterior to the formation of the Olenel/us beds; and the same may 
be the case with the beds containing the Proto/envs fauna in Canada, for this 
fauna is very different from any known in the Olenellus beds, or at a higher 
horizon, though Mr. G. F. Matthew, to whom geologists owe a great debt for his 
admirable descriptions of the early fossils of the Canadian rocks, speaks very 
cautiously of the age of the beds containing Protolenus and its associates, Note 
withstanding our ignorance of pre-Cambrian faunas, valuable work has recently 
been done in proving the existence of important groups of stratified rocks deposited 
previously to the formation of the beds containing the earliest known Cambrian 
fossils; I may refer especially to the proofs of the pre-Cambrian age of the 
Torridon sandstone of North-west Scotland, lately furnished by the officers of the 
Geological Survey, and their discovery that the maximum thickness of these 
strata is over 10,000 feet.s Amongst the sediments of this important system, 
more than one fauna may be discovered, even if most of the strata were accu- 
mulated with rapidity, and all geologists must hope that the officers of the Survey— 
who, following Nicol, Lapworth, and others, have done so much to elucidate the 
geological structure of the Scottish Highlands—may obtain the legitimate reward 
of their labours, and definitely provethe occurrence of rich faunas of pre-Cambrian 
age in the rocks of that region, 
But, although we may look forward hopefully to the time when we may lessen 
the imperfection of the records of early life upon the globe, even the most hopeful 
cannot expect that record to be rendered perfect, or that it will make any near 
approach to perfection. The posterior segments of the remarkable trilobite 
Mesonacis vermontana are of a much more delicate character than the anterior 
ones, and the resemblance of the spine on the fifteenth ‘body-segment’ of this 
species to the terminal spine of Olenelius proper suggests that in the latter sub- 
genus posterior segments of a purely membranous character may have existed, 
devoid of hard parts. 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 mem- 
branous, 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 disappeared, leaving no trace of its existence, in which case we are not 
likely ever to obtain definite knowledge of the characters of our earliest faunas, 
1 See I. Noetling, ‘On the Cambrian Formation of the Eastern Salt Range,’ 
Records Geol. Survey India, vol. xxvii. p. 71. 
2G. F. Matthew, ‘The Protolenus Fauna,’ Trans. New York Acad. of Science, 
vol. xiv. 1895, p. 101. 
3 Sir A. Geikie, ‘Annual Report of the Geological Survey [United Kingdom] .. « 
for the year ending December 31, 1893.’ London, 1894, 
