This establishes the use of chert/flint and is a continuation of form although different in construction.  As we know flint was exported so a variation in construction should be expected.  The same form can also be seen on a New Caledoean club if you scroll through Oceania.  The same bird head club,pick,war hammer? is widespread, seen in many Islands in these parts of the South Western Pacific. 
http://webprojects.prm.ox.ac.uk/arms...a/1900.55.178/