Finding Katahdin Document Packets, Chapter 7, Section 1
Chapter 7, page 198-200.
During the spring river drive, river drivers travelled with the newly cut logs downstream by walking on top of them as they floated down river. The drivers would dislodge logs from jams and direct them down river until they reached the sawmill.
These drivers are pictured with tools known as "cant dogs" or peaveys, which were used to help drive the logs downriver.