136 Proceedings of the Royal Irish Academy, 
presented to us by Professor Harkness.* We showed these structures 
to be unmistakably eozoonal." It consequently gave us mucli plea- 
sure in finding that our Strath specimens afford additional evidences 
supporting the view we have taken in the discussion. 
In the Skye ophite the mineral silicates consist of sub-translucent 
pale green or yellowish serpentine, which is also opaque and whitish 
where it is granular or flocculent, — a white granule- crystalline mineral 
occasionally displaying cleavage, which we refer to malacolite, — and a 
greenish black one somewhat resembling amphibole, and similar to 
the last in texture ; while the mineral carbonates which enclose the 
latter, forming, as it were, their matrix, occur as calcite and dolomite. 
Cases are common in which the serpentine appears to melt insensibly 
into the malacolite, and the malacolite into the amphibole-like species. 
Similar differences of mineral composition and arrangement characterize 
the Laurentian eozoonal" marble of Canada. 
Sir "William Logan has represented a laminated specimen, from the 
Calumet, in which the mineral silicate consists of white pyroxene"f 
or malacolite. In this respect it is identical with the Skye specimen 
represented in fig. 3, pi. xiv. 
Principal Dawson has represented another specimen from Burgess, 
with dark green loganite" and dolomite in alternating layers. J The 
Skye specimen, shown in fig. 4, pl.xrv., we strongly suspect is the same ; 
as its greenish-black mineral appears to be identical with, or closely 
related to, loganite ; a variety which Dana considers to be a pseudo- 
morph after amphibole ;§ while its mineral carbonate appears to be 
dolomite. 
The finest specimens of the two last varieties were procured from 
near Torrin ; where the serpentine, which occurs as strings and inde- 
finite aggregations, is not abundant. 
The layers of mineral silicates in the Canadian ophite, also the 
grains when separated and irregularly arranged, are considered to be 
casts of the chambers" of Eozoon ;" and the interlaminated or inter- 
stitial calcite is taken for its skeleton." In these two features, the 
presumed organism comes well out in the Skye ophite ; as it also 
does in its remaining features — the ''nummuline layer" and "canal 
system." 
Professor Harkness's specimen shows the grains of serpentine in 
many cases invested with aciculi, closely agreeing in their parallelism 
and cylindrical form with those of the nummuline layer" in its 
typical state, as characterizing the Canadian rock. With the excep- 
tion of a few rather obscure traces, here and there, we have not yet 
detected any good examples of this feature in our recently acquired 
* " Quart. Journ. Geol. Soc," vol. xxii., p. 204 ; " Proc. Roy. Irish Acad.," 
vol. X., pi. XLIV., fig. 10. 
r "Geology of Canada," 1863, p. 49, figs. 3 and 4. 
X " Quarterly Journal of the Geological Society," vol. xxi., pi. vii., fig. 1. 
§ System of Mineralogy," 6th ed., pp. 221, 242, 496. 
