Table 2. Weight % nitrogen (%N), weight % carbon (%C), % yield of gelatin relative to undemineralised bone starting weight (% collagen), and Raman organic-phosphate ratio [C-H/PO₄ ³⁻ (ν ₁)] for eight samples for which stable isotope analysis indicates weight % nitrogen at extremely low levels (7 µg or less), including one sample with extremely low weight % carbon.

Raman ID	Burial no.	Archaeological phase	% nitrogen w/w	% carbon w/w	% collagen	Raman ratio
1	560	Neolithic	0.11	2.11	1.88	-
4	80	Neolithic	-	3.43	0.12	0.189
6	146	Bronze	-	6.76	0.27	0.150
7	189	Bronze	2.74	9.28	6.00	-
10	532	Bronze	-	3.44	0.60	0.150
11	550	Bronze	-	1.04	1.75	0.247
31	479	Iron	-	-	0.16	0.208
32	516	Iron	-	3.72	0.40	0.295
37	329	Iron	-	1.85	0.26	0.147
39	481	Iron	-	1.27	0.79	0.145

Two further samples included here (burials 189 and 560) could not have their Raman ratio determined due to fluorescence. The %N, %C, and the atomic CN ratio [Atomic C:N  =  (%C/%N) ×1.1666] from stable isotope analysis are provided to illustrate mass spectrometry indicators of protein survival. The % collagen yield is calculated from bone weight before demineralisation.