The remains were found on private land in Station Road, Hatfield, Doncaster, on Friday.
Enquiries are ongoing to establish if these belong to Mrs Howells, who was last seen in Harrogate in February.
Susan’s family have also been informed.
Two men have been charged in relation to her disappearance.
West Yorkshire Police confirmed Dale Tarbox was charged with Susan's murder and 60-year-old Keith Wadsworth, has been charged with preventing a lawful and decent burial.
They are remanded in custody to appear at Leeds Crown Court on Wednesday, October 30.
Senior Investigating Officer, Detective Chief Inspector Vanessa Rolfe, of West Yorkshire Police’s Homicide and Major Enquiry Team, said: “Our thoughts remain with Susan’s family at this difficult time, and they are being supported by specially trained officers as our enquiries continue.”