indications being that they were displaced a very long time ago. This would point to some severe shock or series of shocks caused by earthquakes. That such disturbances have occurred in this locality, Professor W. H. Sherzer proves in his monograph on the Glaciers of the Rockies and Selkirks (1904). Professor Sherzer found at some distance from the present ice-tongue of the Illecillewaet Glacier which is but seven miles or so from the Caves, two moraines composed of large blocks of quartzite. one at least being estimated at some 2,000 tons weight, retaining the original shape in which they were cast from the peaks above. To distinguish such moraines from ordinary moraines composed of ice-worn boulders. Professor Ralph Tarr, an authority on glaciers, has named them Bear-den moraines from the resemblance of the openings between the great blocks to bears' dens.
Mr. Wheeler asks how and when these moraines were formed, seeing that no glaicers of this age are capable of transporting such a load, and no like quantities of material necessary to form that kind of moraine, are ever now found on the névé below the peaks. And he directs us to Prof. Sherzer's empirical answer to the question, who cut down trees between the two moraines mentioned and counted their rings. The oldest was found to be 580 years old. Allowing for the time required to collect sufficient soil to permit growth at all, the age of the oldest moraine would be more than <300 years. Allowing again for the time necessary to carry the material forming the inner moraine, the earthquake would have occurred during the thirteenth century. That a seismic disturbance occurred in old Canada as late is the seventeenth century is recorded in the "Jesuit Relations" translated by Prof. Thwaites. A bit of the record is quoted: "On the 5th of February, 1663, towards half-past five in the evening, a loud roaring was heard at the same time throughout the length and breadth of Canada On level ground, hills have arisen: mountains on the other hand have been depressed and flattened. Chasms of wonderful depth, exhaling a foul stench, have been hollowed out in many places, plains lie open far and wide where there were formerly very dense and lofty forests. Cliffs, although not quite levelled with the soil, have been shattered and overturned."
Mr. Wheeler concludes his thesis concerning the making of these underground chambers in these terms: "If bear-den moraines can be so accounted for, it is not unreasonabie to assume that a seismic disturbance once shattered this bed of crystalline limstone and precipitated Cougar Creek into subterranean channels which the water and time have enlarged to their present size; moreover, that subsequent shocks are responsible for the large quantities of debris that litter their floors. This hypothesis would explain the crack of the Gorge and similar chasms beneath the surface."
Viewed in the light of an earthquake, the subterranean waterways (for the most part now in disuse) comprising the Caves are of comparatively simple origin. They are of exceeding interest on account of the unexpected forms of the various chambers, corridors, and potholes; but more for the opportunities offered to study crystalline limestone structure and the erosive action of the prehistoric stream in conjunction with the sediments carried by it at flood-stages in the past.
