Since the discovery of silver cobalt ores at Cobalt in 1903, exploration has shown the adjacent country to be locally enriched by mineral veins of the same character and genesis. At the close of 1907 an area 65 miles long in a north and south direction, and about 45 miles wide, extending from Lake Timiskaming and the Ontario-Quebec boundary westward, was known to include at least ten mineralized districts besides the principal one at Cobalt, of which the most recently found lie near the Montreal river. It has also become known gradually that these deposits are closely connected with the post-Huronian quartz diabase of the region. This diabase was known to extend for a very considerable distance farther west, leading to the inference that more discoveries were to be expected in that direction. The spring of 1908 saw interest centred upon the Montreal River finds, and early in the season active exploration had commenced. The Montreal river, up to that time, had not been regarded with special favour, the diabase being considered of no economic importance, but with the new conceptions gained by exploitation of the silver-cobalt district, this formation in the west began to attract attention. At the beginning of the field work, early in July, a considerable number of prospecting parties were on the ground, as far west as Duncan and Pigeon lakes. During July and August this movement, encouraged by the succession of mineral discoveries that were being made near Bloom and Everett lakes, increased steadily, in spite of the scarcity of available topographical and geological information dealing with the region. Early in August discoveries of native silver were made almost simultaneously by Messrs. Mann and associates, and by Messrs. Crawford and Dobie on the west side of Gowganda lake, but were not made public until the first week in September when the claims were recorded at Elk Lake and specimens were exhibited. Twenty-four hours later the leading canoes of an inrushing body of prospectors had reached the new field, and within two weeks most of the promising country between Gowganda and Elkhorn lakes and northward had been staked, regardless of the mineral discoveries necessary to validate the claims. Since then numerous discoveries have been made, and the news of a new silver field, until recently confined to the Montreal River and Cobalt districts, has spread widely. As a consequence, a mid-winter rush is now in progress, and hundreds of prospectors, regardless of deep snow and severe cold, are entering the country. Much inadvisable staking will be done, no doubt, before spring, but the disappearance of the snow and reopening of river navigation will certainly be followed by an increased rush of prospectors. SUMMARY AND CONCLUSIONS.