προσχοῦν

From LSJ

καθάπερ ὄφις παλαιὸν ἀποδύεται θώρακα → just as a snake sheds its old skin

Source

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.