These look to me like type B cut nails circa 1810 - 1900. Horseshoe nails usually are filed or made with a very sharp point, where common cut nails are square at the tip. how long are they?
They are not finger nails that's for sure. But how many did you dig? An old building or barn around? Congrats! They make great shadow boxes or conversation pieces.
Before my house was built in 2000 there were buildings from the 1950s from camp carson in the area but why did they use square nails? The two big ones are 3 and a half inches and the small one is 3 inches long.
Square nails are still used today, most commonly for masonry. I save old ones when I'm demoing walls here and reuse them when I want to make a piece of trim work look old. They turn up everywhere though it seems...