No. 4.] HUNT — ON CAMBRIAN AND SILURIAN. 437 



must have had an existence, and moreover, that even at this time 

 in the history of our globe, an enormous period had elapsed 

 since life first dawned upon it." 



The facts insisted upon by Hicks do not appear to be incon- 

 sistent with the view that at this horizon the trilobites had 

 already culminated. Such does not, however, appear to be the 

 idea of Barrande, who in a recent learned essay upon the trilo- 

 bitic fauna [1871] has drawn from its state of development at 

 this early period, conclusions strongly opposed to the theory of 

 derivation. 



The strata holding the first fauna in south-eastern Newfound- 

 land, rest unconformably, according to Mr. Murray, upon what 

 he has called the Intermediate series ; which is of great thickness, 

 consists chiefly of crystalline rocks, and is supposed by him to 

 represent the Huronian. He has however included in this inter- 

 mediate series several thousand feet of sandstones and argillites 

 which, near St. Johns in Newfoundland, are seen to be uncon- 

 formably overlaid by the fossiliferous strata already noticed, and 

 have yielded two species of organic forms, lately described by 

 Mr. Billings. One of these is an Arenicolites, like the A. 

 spiralis found in the Lower Cambrian beds of Sweden, and the 

 other a patella-like shell, to which he has given the name of 

 Aspidella Terranovica. [Amer. Jour. Science, III, iii, 223.] 

 These, from their stratigraphical position, have been regarded as 

 Huronian ; but from the lithological description of Mr. Murray, 

 the strata containing them appear to be unlike the great mass 

 of the Huronian rocks of the region. Their occurrence in these 

 strata, in either case, marks a downward extension of these forms 

 of paleozoic life. 



Mr. Billings has described from the rocks of the first fauna 

 certain forms under the name of Archeoci/athus, one of the 

 species of which, according to Dr. Dawson, belonged to a cal- 

 careous chambered foraminiferal organism similar in its nature 

 to much of the Stromatopora of the second, and closely related 

 Coenostroma of the third fauna. All of these Dawson shows to 

 have strong affinities to Eozoon, which is represented by E. 

 Canadense of the Laurentian, and by similar forms in the newer 

 crystalline schists of Hastings, Ontario, as well as by the E. 

 Bavaricum of the upper crystalline schists of Bavaria. The 

 succession of related foraminiferal organisms, is farther seen in 

 the Devonian limestones of Michigan, where occur great masses 



