UK hallmarks on ladies gold wristwatch by: Anonymous
Hi Dawn thank you for writing in.
What a lovely dainty ladies gold wristwatch. The triangle in a square cartouche with the corners cut off, is for UK - Birmingham on all ct grades except 24ct Gold on Local & Imported Wares - ca 1904 - Present
The maker is : G. BRYAN & Co. (Silversmiths, Birmingham, UK) - ca 1900 - 1940s
the three digit number .375 is the decimal value for 9 carat gold.
the letter Z would be the Birmingham date letter. possibly 1924 but you need to check.