1917 Sibul Springs, Bulacan Postmark

1 JULY 1917: SIBUL SPRINGS, BULACAN to MANILA
Extremely rare registry postmark of the short lived SIBUL SPRINGS, BULACAN Post Office.
With envelope registry control number  "2" and "1" under it to denote Registry Book Number.

28c Franking with red manuscript cancel and crude large "R" black killers.

NO SIBUL SPRINGS, BULACAN CDS EXAMPLE HAS BEEN REPORTED