A large handsome agricultural stone trough with rounded edges and 'through bolts' to one end. In times past, many early troughs were chiselled by hand from blocks of stone. This later type was made by using a huge stone cutting saw which leaves distinctive circular marks in the stone (see photos).
Typically these slabs were then held together using large iron bolts and either lead or mortar was used to seal the joints.
A substantial trough or planter with sloping ends and rounded upper edges. One of the long sides is missing and end piece and hence the bolts.