Stable carbon isotope analysis

no, but i've recently read a paper on stable nitrogen isotopes in clam shells as a tracer of wastewater inputs (Aquatic Biology 2008, 4:99-111). Someone else was using this technique on historic oyster beds in Florida, but I haven't seen the paper yet, just an abstract.

I'm involved with a project that occasionally samples faunal bone. We generally prefer to sample short-life plants, however. (We've been lucky enough to be able to sample date and pomegranate seeds, for example.) Snail shell has its own difficulties dating, particularly that of water snails, who often ingest fossil carbon from groundwater.

Why do you ask?