So, the part of creek this came from is composed of QT, QAL, and antique glass it seems. There are plenty of fossils too, when I washed out sand from this bottle the little shell was left, and I have tried to get it out but afraid of breaking it. All the recent shells in this creek are from Asian clams and mussels, from what I can tell this looks more like oyster shape. Got the best pictures possible through the pitted glass, so could this be a fossil?