The photograph is a quarter plate ambrotype measuring 2 3/4 x 3 1/4 in what is left of a hinged case. An ambrotype is a very early type of photograph used mainly in the 1855-1865 period. It is a negative reversed image on glass that, when backed with a black material, appears as a positive image. This scan of it has been reversed here to make the scene appear normal.
Exterior ambrotypes are quite rare, and exterior ambrotypes where the location can be identified rarer still. It is certainly one of the earliest photos of a Talbot County scene.
In the 1960s, Sallie Caulk identified the man in the buggy as her father John K. Caulk Sr. who was quite fond of his horses.