'Mound' signifies truths not appearing because they are falsified.

(Референци: Apocalypse Explained 543)

Fifty is also half of 100, which has a similar meaning; the Writings tell us that when used together with 100, fifty represents an intermediate state. God rested on the seventh day of creation. That represents a state of holiness and tranquility that was preserved in the form of the sabbath. Holier still was the seventh sabbath, which happened every 49 days. The Israelites would follow that solemn day with the “feast of the seven sabbaths” on the 50th day, and for similar reasons had a jubilee year every 50th year. For these reasons, among others, “fifty” in the Bible is the completion of a cycle, and in most cases represents fullness or sufficiency.