Note 106 — Chapter XX

The dams of "crib-work" were formed by laying flattened pine logs along the whole outer edge of the work, and at intervals of from 5 to 10 feet parallel therewith throughout the whole of the breadth, connected with transverse timbers firmly treenailed and notched into them. When one course was formed, another was laid upon and firmly treenailed to it. After two or three courses were laid, transverse timbers were placed over them close together, so as to form a flooring, on which stone was placed to suit the crib as the work progressed. When the under side of the crib touched the bottom, it was carefully filled with loose stones and clay puddle to the water level. The process of puddling and pumping out the water, and building up the pier within the dam thus formed, then proceeded in the usual manner. In some cases a powerful steam dredge was employed to clear out the puddle-chambers.