He discouraged vaccinations because disease was a natural means of population control.
Thomas Malthus worried that the amount of resources ( such as food and water) in the world would not be able to keep up with the increasing number of population in the world.
He believed that diseases are natures'ways of population control to ensure that the resources is enough to accommodate all organisms in the world. Because of this, he believe vaccinations as interference of the natural order.
Keeping in mind the description of the stone point given in the story, we can state Marshall the rancher was looking at a Folsom point.
As it's known, a Folsom is a kind of stone point with a leaf-like shape which has a concave base and wide, shallow grooves/flutes running almost the entire length of the point.
It was a time of relative peace when people felt free to travel and trade
