The overground between a second disappearance and re-appearance of the stream is called Mill Bridge from the subterranean noises as of a gigantic mill in operation. The stream now appears at the bottom of a deep rut called the Gorge and finally disappears into the bowels of the mountain.
For half a mile the subterranean stream has carved out a series of passages, gradually sinking to lower levels and leaving a tier of galleries and winding corriders above. They are dark and wet and very difficult to travel, owing to débris dropped from the roofs to their floors; and they are intersected by precipices and dangerous cracks. No one can safely or possibly enter these underground passages without the official guide, who is employed by the Government to be here during the summer months. The rock is a marbleized limestone, varying in color from very dark blue, almost black, shot with ribbons of calcite, through varying shades of grey to almost white. There are no stalactites or stalagmites worthy of the name. Geologically these caverns are of much interest owing to the very marked pot-hole formation throughout.
Route: By the Loop and Cougar pony trail as described above. Time required: The expedition can be made easily in one day, including the excursions via Baloo Pass and Bear Creek. Those Wishing to make a thorough examination of the valley and the caves are advised to spend a night at the cabin, although the accommodation (1911) is not good. (See Monograph on the Caves.)
Cyprian Peak—Name: By the Topographical Survey after "Cyprian," Bishop of Carthage in the year 248; with reference to the Bishop's Range.
Altitude: 10,712 feet.
Location: The westerly of the two highest peaks of that range, Augustine, 10,762 feet, being the higher one.
First Ascent: By Messrs. Holway, Butters and Palmer in 1908. The ascent was made from the Black Glacier. A rock climb of no great difficulty. For inexperienced climbers a guide is necessary.
Route: Reached from Glacier House via Asulkan and Donkin Passes. The ascent may be made either from the Bishop's Glacier, or by crossing the western end of Bishop's Range from Black Glacier as in the present case.
View: From the summit there are very fine views of Purity and Dawson Ranges.
Time required: The expedition requires three days of fine weather and two nights out at a camp on Mitre Creek flowing from Bishops Glacier. All camp outfit must be carried on human shoulders. Porters are available.
Copperstain Peak—Name By the Topographical Survey with reference to traces of copper ore found among its rocks.
Altitude: 8,613 feet.
Location: On the east side of the pass at the head of the west branch of Grizzly Creek and north branch of Spillimacheen River. A long peak, easy of ascent, with a number of mineral locations staked out along its base, opposite the pass.
Corbin Pass—Name: In relation to Corbin Peak.
Altitude: 6,650 feet.
Location: Between the north and south branch of the Illecille-
