προσχοῦν
From LSJ
Greek > English (Woodhouse Verbs Reversed)
bank up, throw up earth (see also: προσχῶ, προσχόω)
Lexicon Thucydideum
limum aggerere, to heap up mud, 2.102.3,
PASS. 2.75.4,
qua agger adstruebatur, where an embankment was being built up.