That seems like Heaven. I love suspender ends. I call them "ends" because I have found a few in an 1870s context which have "suspender ends" embossed on them.
The smaller square to rectangle buckles are actually from the cinch strap on the back of a vest. I also noticed elements from ribbon belts or sashes. The little rings were used to attach the actual suspender ends to a hook or button on the waistband of the pants. The suspender ends were not worn up at the chest but down at the waistline of the pants. It looks like somebody threw away a bunch of different clothes there.
Anyway, great finds. Maybe dig a little bit in that spot and see what turns up deeper and under the rocks.