Questions On Ancestors Marriage Info

Hi everyone:
I recently ordered a microfilm and found my Great Grandparents Marriage Info from 1930, one of the things I learned was that my g-grandmother Leonor Miranda was 17 years old and was originally from Carrizal de Arteaga and the daughter of Dario Miranda and Cenobia X who were living. I was wondering if anyone knows where the Carrizal de Arteaga is located and I was also wondering what could be some reasons her mothers last name was listed as X ?? Here is a link to the image of the Marriage Info.

http://www.nuestrosranchos.com/en/image/view/19376/_original

Rafael Meraz