A Question About A US R.p.o.'s Name

What place was the "C.C." in San Antonio & C.C. R.P.O.?
The definitive list of all U.S. RPO's published in the Postal Bulletin in 1926, unfortunately, lists just that abbreviation without explanation.

Corpus Christi.

Thank you!

FYI for all, I was unfamiliar with this list so went searching and found it titled "Official R.P.O. Titles and Abbreviations" as part of Postal Bulletin #14125 dated July 9, 1926, which would be only current to mid-1926 and would not include historic or future R.P.O. route names. Yes, it is quite abbreviated! The listings of the Mobile Post Office Society are my go-to source for teasing-out mysterious RPO's..