Hi @joseph-dumont! A couple of questions: Is there another ridge running perpendicular to the larger ridge? If so, this is the raphe, a remnant of vasculature between the ovule and ovary. Also, do you see any hilar or micropilar scars? These would appear as dots, circles or even ellipses. I would expect to see one or both below the “beak” and perhaps at the opposite end of the “beak”. If it is a seed, knowing the positions of these characters can help us understand the ovule position which in turn narrows down what families your seed could be in. That “beak” is common (though not exclusionary) in seeds with a campylotropous position which would include plants in the myrtle, poppy, cactus, caper and bean families.
Alternatively, this might also be an endocarp, like the pit of a stoney fruit. I’ll check the FLMNH collections tomorrow and get back to you on what we have from the Brule in terms of plants. I know seeds have been found there before but not the extent to which they have been studied. Thanks!