Does anyone know of any archives that contains information of Correo Maritomo?

There is some in the PARS website. But that topic is new to me as I ran across it by chance when I browsed archives in the PARS website.

I think it has to do with transporation of mail from Spain to the colonies and the mainland in Mexico. I wonder if there is some kind of registry or archive of that and the routes or how or where the mail was distributed in Zacatecas, Jalisco, Aguascalientes.