Life and Remains of John Clare: The Northamptonshire Peasant Poet
packman snail
A packman is a traveling peddler carrying goods on his back—Clare doubles the image by making the snail both traveler and merchant, both creature and its shell-home.
rude mark
'Rude' means rough or crude here, not impolite. The shepherd is calculating time by his shadow's length—a peasant's sundial.
Two letters
Probably initials—either the lover's or both lovers' first letters. Tree-carving was the rural working-class version of love letters.
eagle and dove
Traditional opposition: the eagle represents predatory power and surveillance, the dove represents peace and love. Nature chooses sides.