He gave a specific date and place for his birth in the 1900 census, 8/1865 in Victoria, Australia.
I searched the Australian birth records on ancestry and there's no birth recorded anything close to what he said. One never knows how complete those types of records are, but there are 9 Charles Thornton's born in the decade he said, none in 1865, none with the middle initial S. and none with the parents' name he gave.
Yup - neither Charles nor Jennie appear after 1900, excepting his divorce and death.