Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78), in the Caribbean (1878-79), and along the Atlantic Coast of the United States, during the summer of 1880, by the U. S. Coast Survey steamer "Blake," Lieutenant-Commander C. D. Sigsbee, U. S. N., and Commander J. R. Bartlett, U. S. N., Commanding. XXVII. Report on the specimens of bottom deposits.