Help on plow terminology may be found at this Parks Canada resource:
http://www.rcip-chin.gc.ca/application/dvp-pvd/appli/quest-eng.php?text=plow&btnSearch=Search
Respectfully yours
Paul C. Thistle
Solving Museum Worker Task Saturation Blog
http://solvetasksaturation.wordpress.com/2012/08/05/hello-world/