These photos are of dogs used to herd sheep in the Western US from the 19th century onward to the present. Most are from Wyoming and Montana. It is a good illustration of the very wide variety of sheepdog types used. Most look very like today's English Shepherds or Australian Shepherds. Whatever they were, these are the real dogs.
The dogs were incidental to the photos, so these pictures are 'cropped to the dog' from larger ones appearing in "Sheepwagon: Home on the Range" by Nancy Weidel, published in 2001 by High Plains Press. Copyright is to Nancy Weidel.