Table 3.

Surface elemental composition of sample 37.

Element	BE (eV)	% At. Conc.	% St. Dev.
C	284.7	23.1	0.92
N	400.2	1.6	0.64
O	531.7	44.8	0.76
Na	1072.7	0.6	0.18
Mg	1305.2	0.7	0.24
P	133.2	13.2	0.36
Ca	347.2	15.9	0.30