MASON RECORDS ON MICROFILM
Family History Centers (FHC) at LDS Churches and some Genealogical Libraries (i.e.: New England Historical and Genealogical Society in Boston) have the following microfilms of Mason records available for researchers: NOTE: many of these records are now online. 

Mason Town Records 1758-1874, 4 films of the original State’s copy located in Concord, NH ~
LDS film numbers:
Vol 1, 1758-1831….0015221… contains proprietor’s records, province records, vital statistics
Vol 2, 1787-1816….0015222… contains town records
Vol 3/4, 1797-1824….0015223… contains town records
Vol 5/6, 1821-1874….0015224… contains town records
The above includes a very brief index. The Town Records include minutes of town meetings, accounts, tax lists, surveyors records, ear markings. Also births 1710-1850; marriages 1769-1850; deaths 1760-1840. Records are sparse for some years.

In March 1999 the LDS church finished microfilming more of the old Mason records! So they should be available to researchers unable to get to Mason. 
Many are now online.
This is what they filmed:
Marriages, births, deaths: 1850 – 1868
Marriages, births, deaths: 1 March 1862 – 1 March 1879
Marriages, births, deaths: 2 April 1879 – 20 Dec 1900
Marriages, deaths: 12 April 1911 – 12 April 1911 – 18 Nov 1937
Index of Marriage Certificates, compiled by E. O. Jones: 1855 – 1894