"auto" probably is the storage class, it tells what kind of variable this is. Automatic as opposed to "register" which would force the variable to be a register, or "static" or "extern".
The type is not given at all, I think by default it would be "int".
One of the unusual things in this early version of C is that "int" can be used for any word-sized value, including pointers. The type system was very loose.
Even back then this was considered poor practice, however. The first edition of K&R had a subsection entitled "Pointers are Not Integers" (I don't know if that's still in modern editions).
It looks to me like that section was removed in the 2nd edition. Some sections moved around, so maybe I'm just looking in the wrong place, but it's not nestled between "5.5 Character Pointers and Functions" and "5.7 Multi-Dimensional Arrays" like it is in the 1st edition.
The interesting thing for me is that a variable without a type annotation could potentially store anything. It kind of explains why the language used "int" as the default type of variables declared without a type annotation.
The type is not given at all, I think by default it would be "int".