Zoned by those letters you saw the likeness of three Andes’ summits; from one a flame; a tower on another; on the third a crowing cock; while arching over all was a segment of the partitioned zodiac, the signs all marked with their usual cabalistics, and the keystone sun entering the equinoctial point at Libra.
There are no more uses of "keystone" in the book.
Show samples from other sources
the keystone of campaign reform was the ban on soft money
Friendship with Canada is the keystone in the arch of America’s foreign relations.