"This would give an aggregate of $20,000,000 for the first half of the season--$15,000,000 of which was probably collected by foreigners. During the last half of the season, the number of foreigners was very much diminished, and, perhaps, did not exceed five thousand. At this time, the American immigration had come in by land and sea, and the number of our fellow-citizens in the mines had, as was estimated, increased to between forty and fifty thousand. They were most of them inexperienced in mining, and it is probable the results of their labors were not so great as has been estimated for the first part of the season, and experienced miners. Assuming that the average of half an ounce per day ought to be considered as reasonable, it would give an aggregate of about $20,000,000. If from this we deduct one-fourth on account of the early commencement of the wet season, we have an estimate of $15,000,000; at least five of which was collected by foreigners, who possessed many advantages from their experience in mining and knowledge of the country. "These estimates give, as the result of the operations in the mines for 1848 and 1849, the round sum of $40,000,000; one-half of which was probably collected and carried out of the country by foreigners. "From the best information I could obtain, I am led to believe that at least $20,000,000 of the $40,000,000 were taken from the rivers, and that their richness has not been sensibly diminished, except in a few locations, which had early attracted large bodies of miners. This amount has principally been taken from the northern rivers, or those which empty into the Sacramento; the southern rivers, or those which flow into the San Joaquin, having been, comparatively, but little resorted to until near the close of the last season. These rivers are, however, believed by those who have visited them, to be richer in the precious metal than those in the northern part of the gold region." Adopting the hypothesis that the gold found in these streams had been cut or worn away from the veins in the quartz through which they have forced their way, and considering the fact that they are all equally productive, we may conjecture what a vast amount of treasure remains undisturbed in the veins which run through the masses of rock over a space of forty or fifty miles wide, and near five hundred miles long. Such an estimate would almost defy our belief; yet, if the hypothesis is true, there is no reason to doubt that the value of the gold which that region will yield, is almost beyond calculation.