84 ‘fA Last of Minerals and Organic Remains. 
some fragments, which believe to be the pointed lateral pro- 
longations of the ‘‘ bouclier” of the ogygia genus. Brong- 
niart has figured some imperfect trilobites which Mr. 
Charles Stokes, M. G. S. London, sent him from Llandeilo 
in Wales. ‘These are in great abundance in Lake Cham- 
plain, (M. Leseur) around Montreal, at the falls of Mont- 
morenci, throughout Lake Ontario, and in one instance in 
Lake Simcoe In these places likewise they are mutilated; 
but are in a larger and better defined form, than those of 
Wales. 
I beg to refer to three figures of large unknown tri- 
lobites, published last year in the Geological Transactions 
of London. 
I have by me at present a fine but imperfect impression 
from the cast of an undescribed trilobite from the isles on 
the northshore of Lake Huron. It is a pretty exact oval, 
rather exceeding five inches in length, and two and an half 
inbreadth. ‘The total length appears to have been six inch- 
es. [tis not clear which end represents the ‘‘ bouclier 5” 
except we judge from the position of the articulations, 
which are eleven in number, each one fifta of an inch broad, 
the upper one being an inch and a half from the summit of 
thesupposed bouclier. Of the three lobes, the middle one 
is much tbe largest, that on each side being only five eights 
of an inch broad, and being not quite so protuberant as the 
first mentioned lobe, which itself has a moderate and 
gradual convexity. 
All parts of this remain are full of small transverse curv- 
ed tracings, more or less parallel to each other. 
Ammonite.—Casts of ammonites are plentiful at the east 
end of Drummond’s Island; but are in less number on the 
isles of the north shore of Lake Huron. They occur in 
Lakes Simcoe and Ontario, abound in the brown limestone 
near Fort Wellington, U. C. at the head of Lake St. Fran- 
cis, and at Montmorenci, L. ©. ‘Those are smooth, oval 
and spherical casts of granular limestone, and are about the 
same in size and general appearance. At the last place there 
is avery small kind (one half, to one and a half inches io di- 
ameter,) deeply striated, and invested with nacre or spa- 
those substance. 
Orthoceratites. These exist every where in immense 
quantities,—in all places, occosionally large :—in Lake 
