The clubhead of this early 1900s Excelite driver consists of a wood head completely encased in black vulcanite.  The covering is apparently vulcanized into  place, as the horn and its pegs are identifiable under the vulcanite.  Coating the head with vulcanite would render the head waterproof and less prone to breaking. 

The club is in wonderful original condition.  The shaft is original as is the sheepskin grip. The top of the head is marked "Excelite \ Regd \ Covered." 

This is the actual club presented in TCA2 v1 p369.  A copy of page 369 signed by the author will be included with the club.