Cri/piozoon and other Ancient Fossils. 



219 



In conclusion, it is intere.slii^i,' to note how many large Itut 

 obscure ami pnjltlematical organic remains, all ap))iirentlyof 

 low types and generalised structures, and therefore ditlicult 

 to classify, cluster about the base of the Cambrian, and 

 api)ear to point to a primitive world beyond, of whose 

 other inhabitants we know little else except indications of 

 marine worms, of sponges, of a few Protozoa, and possibly 

 of plants. Like the lloating debris of the land noted by 

 CJohunbus on his westward voyage, they raise our hcjpe 

 that we are one day to reach antl annex to the empire of 

 geological science a new region in which we may be al)le 

 to see the beginnings of those great lines of life that have 

 descended througli the ages, and are alike mysterious in 

 their origin, their development, the decay and disappear- 

 ance of some of them, and. tiie addition from time to time 

 of new types to their number. 



1 may add for the benefit of searchers in this field two 

 practical points: (I) Such organisms as most of those 

 referred to in this paper are not attractive to the ordinary 

 collector ; because externally they shew little of their 

 structure, which becomes manifest only after they have 

 been cut and etched with dilute acid or prepared in trans- 

 parent slices for study under the microscope. There can 

 be little doubt that many of them are overlooked for this 

 reason. (2) In Cambrian and Pre-Cambrian formations 

 fossils are often abundant on certain surfaces or in certain 

 thin layers, while intervening beds of great thickness are 

 barren. Hence the importance when productive beds are 

 found, of working them thoroughly when possible. In this 

 the local collector who can revisit the same spot many 

 times and spend days in working at it, hiis great advan- 

 tages. Otherwise such productive spots can be adequately 

 worked only by spending money in securing good collect- 

 ors and giving them sufficient means for excavation. 



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