From the Union version of the above book:
The Colt "Army" and "Navy" Revolvers were widely issued to the Northern Cavalry. Like the Colt Revolver the Remington Models came in both the .44 cal Army model and .36 cal Navy model. Around 115,563 Remington Armys were sold during the war of which most were made after 1860. The Whitney Navy revolver and Starr (single action) Revolvers were also used. The foreign made Lefaucheux (I assume it is from France) Revolver was the only non Percussion revolver sold to the Northern forces. They were mainly used to arm troops in the Western theater.
For above post here is a Le Mat Revolver:
