444 Sir W. Daivson — The Animal Nature of Eozobn. 



by Serpentine, Loganite, Pyroxene, and Dolomite, an indication 

 t^at a similar mould had been filled by diverse minerals. 



At that time the little leisure I could spare for original work was 

 occupied with Carboniferous and Pleistocene geology, and I had 

 no ambition to invade the great and difficult pre-Cambrian districts 

 of Northern Canada any farther than might be necessary to my 

 vfork as a teacher of geology. In the interest of that work, how- 

 ever, I had gone over considerable portions of the Laurentian and 

 Huronian districts surveyed by Logan and Murray, with the aid 

 of their maps and reports, and had satisfied myself of the great 

 accuracy of their work, which led in my judgment to the following 

 results: — 



(1) That the upper part of the Lower Laurentian of Logan, since 

 called the Grenville Series,^ consisted of truly stratified metamorphio 

 rocks, including great and extensive deposits of limestone, quartzite, 

 iron-ore, and other rocks, evidently of aqueous origin, and that the 

 condition and crystalline and chemical characters of these rocks 

 were not essentially different from those of the altered Palaeozoic 

 beds with which I was familiar in Nova Scotia and New England. 



(2) That the Huronian, a less disturbed, less altered, and in 

 the main evidently a clastic series, rested unconformably on the 

 Laurentian, and was in part composed of its materials. 



(3) That the " Upper Copper-bearing series " of Lake Superior, 

 since known as Kewenian, was newer than the Huronian, but older 

 than the oldest fossiliferous Cambrian rocks then known in Canada. 



(4) That, while the Kewenian and Huronian rocks, and those 

 designated by Logan as Upper Laurentian, indicated by the presence 

 of igneous masses, and, in the case of the two former, by the 

 prevalence of coarse, clastic material, littoral conditions and much 

 volcanic disturbance, the still older Grenville Series was of a character 

 more indicative of long-continued quiescence, accompanied by the 

 accumulation of great calcareous deposits, possibly of organic origin. 



These conclusions were noticed in papers contributed to local 

 societies, in published lecture-notes, and in class-teaching, and were 

 frequently discussed with Logan and Hunt. Accordingly, when, in 

 1863, at the urgent request of Logan, I undertook the microscopic 

 examination of large series of his supposed Laurentian fossils and 

 the containing limestones, as well as of other crystalline limestones 

 of various ages, slices of which he had caused to be made, I was 

 not unprepared to find the curious and beautiful structures which 

 developed themselves in his Stromatoporoid forms, and in portions 

 of the limestone in which they were contained, but which appeared 

 to resemble those of Foraminifera rather than those of Corals. 



The results thus attained, in 1864, were not fully published until 

 after Logan was prepared to sustain them by detailed maps and sections 

 of the district on the Ottawa containing Eozoon, a work extending 

 over many years of arduous and skilful labour ; and until 

 Dr. W. B. Carpenter and Prof. Kupert Jones had studied the 

 original specimens and others prepared for themselves, along with 

 1 By Dr. Sterry Hunt. 



