Some mouths since I received from J. G. Grenfell, Esq., of Clifton College, a few small specimens of igneous rock which he had collected in the year 1880 on Old Providence Island. This is an island in the Caribbean Sea about 90 miles off the Mosquito Coast, in lat. 13°26'N, long. 81°18 W. Itis oval in shape, 4½ miles long from N to S, and 2¼ miles wide. Barely separated from it on the North is a little island named Sta. Catalina. Bit. Grenfell describes the main island as mountainous, with three chief peaks, the highest of which rises to 1,190 ft. Spurs from these terminate on the shore in peaked hills from 800 to 700 feet high.