Simple typo. "(That is, an expression (λx.M) combining with an expression N returns (M) where all instances of x inside of M are replaced by x.)" Are replaced by N.
Another one. "“x̂” ⇒ “^x” → “∧x” → “λx”.]" The first ⇒ should be →.
Well, I had it as → initially and changed it to ⇒ to try to indicate that the first change was a re-casting because Church was adapting Whitehead & Russell's notation for class-abstraction to a notation for function abstraction.