I like them all, but I have to agree those four in your hand are great. The agate one is nice. that one with the broken tip would have been a killer if the tip wasn't gone. Sure some nice point's Steve.
this site has been occupied since the pelican lake , oxbow, duncan hanna times and before
which is at least 6000+ yrs BP
but i think the majority of these artifacts are 500 or less yrs old
and yes the Mandan jack knife is one of the most rare pieces i have ever seen
i have only found one in the last 26 years..and do not know of any others