This is about the slaughter of buffalo. The buffalo bones were 'stamped' on using a potato that I cut out.

The following is quoted from www.history.cbc.ca:

"At one time, there had been as many as 50 million buffalo on the North American plains. Even in the early 1870s, there were herds so vast that it took several days to pass them.

Then two technological advances spurred the rapid slaughter of the buffalo. The demand for buffalo hides surged when a useful tanning method was developed. The method allowed the soft hide to be made into tougher, more desirable leather.

The other advancement was the development of the repeating rifle, allowing hunters to kill buffalo in huge numbers.

Beyond the technology, the United States government also encouraged the slaughter of the buffalo as a strategy to conquer the American plains Indians. American General Phil Sheridan said, "Let them kill, skin and sell until the buffalo are exterminated. Then your prairies can be covered with speckled cattle and the festive cowboy."

By the end of the 1870s, millions of buffalo had been slaughtered for sport, profit and military gain. Killing buffalo even became a past-time as sportsmen from Britain traveled to the plains to take part in the hunt.

In Canada, fur traders, plains natives, and white hunters, helped slaughter about four million buffalo.

When Canadian settlers started farming, the first cash crop for some was buffalo bones, sold by the ton for fertilizer".