Compiled service records consist of a jacket-envelope for each soldier, labeled with his name, rank, and unit. The records contain card abstracts created from original muster rolls, payrolls, hospital rolls, and other regimental information. They also contain images of original documents pertaining to a particular soldier. Some single documents are cross-references for soldiers who appear in the records under more than one spelling.
"Compiled Service Records of Volunteer Soldiers who Served During the Mexican War in Organizations From the State of Mississippi" database with images Fold3 (https://www.fold3.com/publication/771/mexican-war-service-records-mississippi: accessed November 27, 2022)