A singular phenomenon lately occurred in California, by which Lake Merced, a sheet of water, covering about thirty acres, and which is situated seven miles distant from San Francisco, threatens to become dry ground. A shock of an earthquake took place during the night, and in the morning it was discovered that a portion of the lake's boundary had been swept away, and a passage forced by the rushing waters about three hundred yards in width, and ten or twelve feet deep, opening on the sea shore to the width of a mile. Subsequently, a sort of mid-channel hap been formed, commencing a short distance below the origin of the outlet, narrower and much deeper than the first, down which the water seems to have rushed with much velocity, until the lake has been emptied at least thirty feet below its previous surface. This mid-channel has gradually deepened in the centre, forming an outlet down which the waters are yet flowing into the ocean. And now that the outlet has been forced, from its abrupt sides may be seen flowing the gaseous fluids which succeed earthquakes among lofty mountains. It is supposed that the bed of the Lake may have been instantly uplifted, and as quickly have returned to its customary level; thus forcing an outlet through the heav y alluvial by which it was formerly confined.