Asking For Help Identifying The Datestamp On Thie 10 Centavos Mexico Stamo On 1875 Cover

Dear experts,

I am having difficulty identifying this datestamp on the Mexican 10 Centavos stamp on this 1875 cover to San Francisco.





I've tried using ImageSleuth to enhance any hidden characters, as well as ChatGPT and other AI for image analysis but without success. My observations are as follows;

- The upper portion contains "RA"; maybe Vera Cruz?

- The lower portion contains "ATLA"

I searched for towns/cities in Vera Cruz containing "ATLA", but so far I have been unsuccessful in getting a satisfactory clue.

Any suggestions on the post office/town/city name is welcome.

Thank you in advance,
Hironobu

The bottom of the cancel reads the same as the overprint on the stamp .. MAZATLAN