Doncaster Canons or "Doncaster Heads" are canons that consist of 4 loops which are 90* from each other in a + shape looking from above. This type unlike the conventional canon is not as curvy as the Conventional canons but are more flat on top. Their design is very straight and simple.
The Doncaster canon was introduced to John Warner & Sons in 1858 as being a modern design. It was designed by Lord Grimthorpe for a ring of 8 in Doncaster.
Doncaster heads can be commonly seen especially on Warner bells and Gilletts also used it on their bells. Crawley, St John the Baptist has a ring 8 bells all cast by Gillett, Bland & Co which all feature one. The 3rd was recast in 1931 by Mears & Stainbank but they kept it with the same canon however it looks slightly different in appearance.
Sketch of Canon:
Bell mould with a doncaster head mould
Images of bells with the canon:
Crawley, St John the Baptist (4); Lowfield Heath, St Michael & All Angels (Clock); John Taylor & Co, Loughborough foundry; Brighton Fishing museum.