Prof. Bonney—Eozoon at Cote St. Pierre. 297 



with the western side : (1) pyroxenite, about four feet ; (2) patches 

 of serpentine in calcite, about three feet; (3) crystalline micaceous 

 limestone, about twelve feet; this is spotted with grains of pyroxene 

 in the lowest part, and more distinctly banded with mica in the 

 upper part. 



One outcrop only of the upper gneiss, on the left bank of the 

 valley, was examined. It agreed in general character with that 

 seen on the road from Papineauville, being a distinctly foliated, 

 rather fine-grained biotite gneiss, with alternating bands of more 

 or less micaceous rock. Possibly there were also some indications 

 of an intrusive granite, with but little mica. 



The so-called Laurentian quartzite, under the microscope, does not 

 exhibit the slightest trace of a fragmental origin. It consists of 

 quartz, felspar (including microcline), mica (probably a bleached 

 biotite), with a little, rather minute, chlorite, some grains of iron 

 oxide (probably magnetite), and a few microlithic minerals, among 

 them possibly zircon. It exhibits the structure which I have more 

 than once described as very usual in primeval " gneisses," and only 

 differs from them in being exceptionally rich in quartz. Into the 

 microscopic details of the "Eozoonal" rocks I abstain from entering, 

 as they have been so frequently described, and content myself with 

 remarking that the peculiar structures, to which appeal has been 

 made in the controversy, are exhibited by my specimens, in some 

 cases very well. I will only add that the malacolite occasionally, 

 the serpentine perhaps rather oftener, in the supposed "chambers" 

 is stained by a black or brownish mineral, and that in one case ^ 

 the darkish grains included in the calcite prove to be in some cases 

 barely translucent, in others fairly so. The mineral then is of an 

 umber-brown colour, which is doubly refracting, and occasionally 

 becomes fibrous near the edge, but otherwise seems to have neither 

 definite structure nor cleavage. I have not been able to satisfy 

 myself as to its nature, but it bears some resemblance to one of the 

 hydrocarbon group. Possibly, however, it is the loganite examined 

 by Dr. T. Sterry Hunt. A like mineral occasionally forms a border 

 to clear grains of serpentine. The calcite often has a "dusty" aspect, 

 due apparently to the presence of a brown or black powder. 



The Rev. J. F. Blake has expressed the opinion- that the granular 

 magnesian mineral in these Eozoonal rocks is frequently olivine. 

 It undoubtedly often resembles the latter mineral, and there is no 

 a priori reason why this should not be present, especially such 

 a variety (or species) as monticellite. Olivine, however, is commonly 

 associated with igneous rocks, so that a little scepticism is justifiable, 

 and some varieties of pyroxene (such as malacolite) appear to be 

 readily converted into serpentine. The reasons also given b}'^ Mr. 

 Blake in favour of his view appear to me inconclusive. Malacolite 

 often exhibits high polarization tints and a similar texture to olivine, 

 and is not seldom, when the grains are rather small, without cleavage. 

 In my own specimens I find it impossible to distinguish, either by 



1 The specimen mentioned above as collected on Levine's Farm. 

 - Quoted by Messrs. Johnston-Lavis and Gregory, loc. cit., p. 274. 



