Maybelle Carter's style involves playing a usually simple melody on the bass strings of the guitar with a thumb pick while playing the associated chords on the treble strings using a finger pick. The style called Thumbpicking is nothing like that.

Justa Picker provided an excellent description of thumbpicking in this thread's initial post. Read the whole thread to learn even more about the details of playing in the Thumbpicking (AKA, Travis picking) style. Thumbpicking is the other way 'round from what Maybelle Carter played. In thumbpicking the thumb plays a heavy bass line with the strings muted to give the effect of a different instrument. The melody is carried by one or more fingers syncopating the melody through a vastly expanded and embellished set of chord changes. Most thumbpickers eschew the use of finger picks but even Merle Travis used them on occasion in his later years.

      - Mark