Whereas the granite plutons of the Central Province are spread over a broad region straddling the suture at the eastern boundary of Sibumasu (Fig. 1), those of the Western Province are confined to the Phuket-Slate Belt terrane, and are bounded on the east by the faults described above, pace Cobbing (2011) who speculates that the Khao Phanom Bencha pluton may be an outlier of the Western Province (Fig. 7).