Unidentified photographer
1874, 14 April (date patent for foreground issued)
Patent mark on a tintype of a portrait of a man with a caricature foreground

Tintype, mark, patent date
Private collection of Michael Pecosky
The date is for C.M. Coolidge's US patent No. 149,724, "Processes of Taking Photographic Pictures", 1874, 14 April (patent issued).
 
Thanks to Beverly Wilgus for this information (7 December 2018).
 
LL/67040