Marine univalves, fossil, [424].

Markfield, [903].

Marlstone of the Lias, [29].

Marsupialia, fossil, [803].

Marsupites Milleri, [289], [299].

Maryland, U. S., [593].

Massachusetts, [769].

-------------, biped foot-tracks of, [769].

Masson Hill, [870], [873].