Table 1. Samples used in this study and their identification.

Site	Name of site	Period	Dental calculus samples	Not inhibited samples	mcrA (+)	16S (+)	Positive (either 16S+ or mcrA+)	Identification
								M. oralis	CandidatusMethanobrevibacter sp. N13	M. bourgensis	?
A	Saint-Mitre-les-Remparts	16th–18th century	37	16	7	8	10	3	6		1
B	Rayettes (Martigues)	1720–1721	11	6	3	6	6	4	0		2
C	Forbach	1813	12	6	3	3	3	1	0	1	1
D	Avosnes	14th century	1	1	1	1	1	0	1		0
E	Les Fedons	1590	29	17	10	14	14	0	11		3
F	Douai	1710–1712	10	10	6	8	8	3	5		0
	Total	14th–19th century	100	56	28	40	42	11	23	1	7