From my database of TX field officers:

Name: John Randolph Johnson
Civil War Service: Capt., Johnson's militia company. Major, 20th TX Cav
Born: c. 1822, AR
Died: Feb., 1866, in the explosion of the steamboat W. R. Carter on the Mississippi River near Vicksburg
Occupation: Merchant in Kaufman Co., TX
Education:
Other:
Buried: Vicksburg
Grave location:
References