C.R. Martin button

Queensland Railways

11th Regiment of Foot (North Devonshire)

Backmark: C. Pitt & Co 50 St Martins Lane London Charles Pitt & Co operated from 50 Martins Lane from 1875-1895, so this is after the period in Australia of 1845-57.

For another example:

http://www.austbuttonhistory.com/uncategorized/20th-november-2020/

Woolworths

General Plastics must have liked this design, as they produced it in both sew-through and (with out the holes) shanked versions.

Shanked and pearlised versions.