Major, U. S. Marine Corps

Musicians, called "Musics", wore bright jackets.
They were non-combatants but often doubled as stretcher-bearers.

Officer's Dress Shoes
Shoes could be worn on either foot.
Not until 1851 was military footgear made to the shapes of the right and left feet.

Topographical Corps, U. S. Army
Full Dress
The ostrich plume and heavy embroidery on sword belt, cuffs and collar mark this man as an officer.
The elite Topographical Engineers corps included John C. Fremont, George G. Meade, and Joseph E. Johnston.

The image above displays a collection of various contemporary uniform pieces rather than a depiction of a single uniform.
The coat, trousers, and chapeau belonged to Captain George Hughes and reflect the 1839 clothing regulations. The Topographical Engineers saber has no name on the blade. The belt is a dress belt from the pre-1839 dress regulations and, in the strictest sense, does not belong to the uniform although at the time these belts were frequently worn with the dress uniform. The dress epaulettes are post-1851 as evidenced from the rank on the strap. Finally, the sash should be tied on the right side rather than the left for the 1839-1851 period.