During a recent residence in Portugal I paid a visit in Feb. 1877, to Coimbra, and while standing on the tower of the University, whence a magnificent view of the surrounding country can be obtained, I was much struck by the immense accumulation of sand deposited over a wide area on both banks of the river Mondego, by whose margin the city stands. A considerable, though, comparatively speaking, a small quantity was of recent date, and was evidently brought down by the heavy rains in the months of November and December of the previous year, which had produced destructive floods throughout the country, and had here greatly threatened the low-lying parts of the town. I was informed that every year a large quantity of new sand is spread out over the valley; but the shortness of my stay here precluded any attempt to estimate the yearly additions to the fluviatile stratum.