A deed with no bearings or distances calls for 'starting at the bridge' (on a non-navigable creek) - doesn't say center or which side. Normally, unless stated otherwise, this boundary would be the center of the creek. Then down the creek along the cliff (cliff is on the same side where the subject property is located); then on down the creek to a tree (which side is not stated), then down to a tree that is on the opposite side of the creek. There is an old, abandoned dirt road with no recorded width or ROW that traverses the subject property and crosses the creek downstream from the cliff and then runs upstream along the other side to the bridge. My guess is the boundary is along the cliff side, and the tree on the other side is just to indicate where the boundary leaves the creek and starts up the hill.
What do the adjoining properties deeds describe?
Sounds kind of like an aliquot part... it's whatever you say it is.