Mother Shipton was a prophet who lived in North Yorkshire during the 16th Century, and as far as we can tell had nothing to do with Seaton Snook.  

 

This is certainly far more technically/physically difficult to play than any of the other pieces that have been found so far.  The relatively complex chords for what is supposedly a beginner primer, indicate this is from a much later part of the book, and that many pages are indeed still missing.