What is "blackberrying"

Usage examples of "blackberrying".

It was rather outmoded, and its original blue had faded to an indeterminate gray, but it was quite good enough for blackberrying, and not even Nurse would cry out censoriously if it became stained.

At the first opportunity we meant to make a quiet trip up there with hammer and drill to obtain specimens for assay, but for one reason or another we did not get round to it until August, when we planned the blackberrying excursion.