DOWLING. 
SUTTON MILL LAKES 
25 F 
steep slopes and nearly bare surface.s, to about 100 feet above the lake 
level. Hack from the lake ; some of the hills seem to atiain still higher 
elevations, of probably over 200 feet. I’he .sketch-map on the oppo.site 
page shows the trap-crowned hills of tins vicinity. On the east siile a 
series of tine-grained compact red and black beds is o.vposed , on the 
west the exposures are of trap to the water’s e^lge. The fault, 
which runs north and south, here has a downthrow to the west of 
over 50 feet, carrying all the stratified lower rocks beneath the lake 
level. The only sections of the.se hed.s to lie seen are on the east side, 
principally in the vicinity of the p-Ttage. Just at this place a small 
cap of trap stands near the gorge and behind it, to the east., is a narrow 
valley not eroded as deeply as the cut at the stream, but only to the 
upper beds of the sandstone and slate. Through this valley the road 
for the portage pa.sses, rising to about fifty feet between its extremities. 
The highest point that the trail reaches is over a ledge of iron-bearing iroa bearing 
slafce.s, above which on either han<i rise tlie rough hills ui Iih}i. As the 
.slates are nearly horizontal, the total thicknes.s exjxisedon the portage 
road, together with tliat brought up by a slight anticline just to the 
south, reprc.sents all that was seen of the.so rocks. Northw’ard the 
beds decline at a .slight angle, so that tliey reach the water and are 
brought up again for a short distance at the second narrow.s, or tlie 
point marked A on the sketch. Here the fault runs to the west of 
the projecting point so that the same hods appear on both sides of the 
channel, but the western point is separated from the rock.s to lljc west- 
ward by an accumulation of drift material forming a low spit with 
sandy bays on either side. The deep channel is eroded thntugh the 
sandstones, to a deptli of 140 feet. The section published in the sum- 
mary report is that of the rocks to the south of the portage road. The Jasj.ilytfs. 
jaspilytes when examined in thin section are found to be compacted 
•sandstone.s, thegr.aiivs of wbicli are stained to various .shades of red by 
the presence of iron oxide, which forms in many cases a coating around 
them All the beds are made up of fragments of various degree.s of 
fmenc.ss arranged in a natural order, (he coai>er at the ba.se and the 
finer at the top. The .slaty beds ju.st beneath the (rap are made up of 
much finer grained particles of quartz, coloured dark liy a matrix of 
opaque fine-grained material .separating tlio grains. 8oino at least of 
this mass is probably magnetite. 'I'lie (piartz grain.s con.stitute 50 per 
cent of tluj mass, an<l of t-his about h.'ilf are of red chalceilonic quartz 
ntid the other pai't clear grains made up of a mass of mosaic ijuartz. 
The red beds beneath are of much coarser grain, and are seen, even in 
a hand specimen, to be inaile up of rounded particles of red colours. 
