There are many references in the Bible to stones and stone cutting, e.g. 1 Kings 5.17, Matthew 21.42 and 1 Peter 2.5. The mountains around Jerusalem are composed of limestone that has a characteristic layering. To quarry this limestone, the face of the stone first had to be straightened. Here we see the stonecutter on the right cutting 4-inch wide channels on all sides of the rock except the bottom. Another worker pours water over dry wooden logs that have been jammed into the channels. The water causes the wood to swell and the lateral pressure on the stone block makes it split away from the rock. Because the limestone lies in natural horizontal layers, the blocks would split along relatively clean horizontal lines.