388 
THE GEOLOGIST. 
the eastern townships and forms many isolated hills, the whole of thera of 
small size with the exception of the Great Megantic Mountain, which 
occupies an area of about 12 square miles. It is composed of white quartz 
and white orthoclase feldspar, with black mica. An area of this rock 
occurs in Stanstead, covering 6 square miles, and forming Biby Plains. 
Another occurs in Barnston, from which the second sample exhibited has 
been taken. Granite of the same character, and probably of the same age, 
is widely distributed in the State of Maine, and is traceable to New Bruns- 
wick, where it is overlaid by the carboniferous rocks. 
Marbles are exhibited from the Laurentian, Quebec, Chazy, Bird's E3^e 
and Black River, Trenton and Upper Helderberg formations ; and ser- 
pentine from Oxford, Melbourne, and St. Joseph Beauce. The band of 
serpentine from different places on which the samples have been obtained 
has been traced on the south side of the St. Lawrence, from Potton. 
to Cranbourne, liO miles ; in 40 miles of which it is twice repeated by 
undulations, giving an additional 80 miles to its outcrop. It is again 
recognized 250 miles further to the N.E. in Mount Albert, on the Shick- 
shock Mountains, and about 70 miles furtlier in Mount Serpentine, 
approaching Gaspe Bay. All the specimens of the rock which have been 
anal3'scd contain small quantities of chromium and nickel, and the band is 
associated in its distribution with soapstone, potstone, dolomite, and mag- 
nesite. The whole of these occur in large quantities, and in them as well 
as in the serpentine chromic iron occurs, sometimes in workable quantities. 
These rocks or others immediately near them contain the metals iron, 
lead, copper, nickel, silver, gold, and with the drift-gold derived from these 
beds are platinum, iridosmine, and traces of mercury. In 1847 these ser- 
pentines, from their distribution, were described in the Reports of the Sur- 
vey as altered sedimentary rock ; and all subsequent observations have 
confirmed this view. Regularly stratified masses have been found in 
Mount Albert belonging to the Quebec group. 
Roofing slates are exhibited from a band of slate in immediate contact 
with the summit of the serpentine. It has a breadth of -i- of a mile, and 
dips about 80^ S.E. Mr. AValton commenced opening a quarry upon it 
in 1860, and found it necessary, to gain access to the slate, to make a tunnel 
through the serpentine, to effect which, and expose a sufficient face for 
working, has taken two years, and cost 30,000 dollars. 
Up to a comparatively recent period, the usual coverings of houses in 
Canada have been wood, shingles, and galvanized iron or tin plate ; but so 
many fires have happened by the use of the former that they are now 
interdicted in all large towns. Those exhibited are from Mr. Walton's 
quarry, which has now been in operation since 1861, and these slates are 
now being sent to distances of more than 500 miles. The strong re- 
semblance between these Melbourne slates and those from Bangor, in 
Wales, and Angers, in France, may be seen by the following analyses by 
Mr. F. Sterry Hunt:— 
Welsh. French. Canadian. 
Snica 60-50 ST'OO 64-20 
Alumina 19-70 20 10 16-80 
Protoxide of Iron . 7-83 lO OS 4-23 
Lime 1-12 r23 0-73 
Magnesia 2-:i0 3-89 3-94 
Potash 3-18 1-70 3 26 
Soda 2-20 1-30 3-07 
Water 3 30 4.40 3 40 
100 03 100 13 9963 
