The editor of the " Dubuque Daily Herald" has received specimens of. coal of a superior description from the coal mines in Des Moines Valley, near Fort Des Moines. It exists abundantly in the vicinity of the town of that name, and is easy of access. A let ter from a committee appointed at a public meeting says that the Des Moines river flows over a smooth bed of coal, the depth of which is as yet unknown while the upper stratum may be seen protruding from the sides of the hills in almost) every direction. The Canals of this State will be open for navigation about the 15th of April. The Ohio Canals will 'be open between the 24th of March and the 1st of April.