Figure 3. {¹H}¹³C CPMAS spectrum of the organic layer of Notodiscus hookeri shells.

The spectrum of the organic layer of shells originating from Branca site are compared to the spectra of ß-chitin powder and to the most abundant L-amino acids found in this layer (G = glycine, L = leucine, I = isoleucine and V = valine). The major peaks of the organic layer can be ascribed to each amino acid, as shown by the dotted lines. The chitin signature, indicated by the C1 to C6 carbon ions, is not detected in the organic layer. Asterisks (*) represent spinning sidebands.