Figured GSP would get a kick out of this paper. Lee, Y.-N. 1997. Looks like one, though. Biochemical and geochemical analysis of bones of ichthyosaurs from this famous site. Organic fraction pporly preserved and the bones slightly altered.
Bones read the same as the sediments in electrophoretic analysis and no apparanet amino acids.
Worked on Stenopterygius. Two references with titles that say enough - on mammals but may be of interest to some. Problems and prospects for carbon isotope analysis of very small samples of fossil tooth enamel. Stable carbon and isotope ratios in ungulate teeth from French Eocene and Oligocene localities. Apellaniz, E. Et a batch of others.