Oh, wow!!!! I hadn't thought of that, and this could be a real possibility due to the proximity of Italy to Barcelona! Thanks for the excellent tip.
Progress:
I did a white pages search for Carcolses in Barcelona. There are three, so at least it establishes the surnname there. Also, there is a geographic place called Carcolse northwest of Barcelona. (Not a whole lot there.
I am still working through all those Barcelona birth certs. Up to page 930 now, so about 500 more to go (four to a page).