101848
July 12 , 1881 , Major Merrill , Seventh Cavalry , assigned to command of " escort to working parties on extension Northern Pacific Railroad , between Little Missouri and Tongue Rivers . "
 Merrill, Seventh Cavalry, Northern Pacific
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Merrill, Seventh Cavalry, Northern Pacific