Hi Dinarina
Irregular marriages were legal in Scotland until 1st July 1940 and could be registered by obtaining a Justice of the Peace's or Sheriff's warrant. These show up in marriage certificates as marriage 'by declaration' or by 'warrant of sheriff substitute'.
From
http://archiver.rootsweb.com/th/read/SCT-EDINBURGH/2006-08/1156284811, a further explanation:
There were two types of marriages in Scotland the 'regular' and the
'irregular.' The regular marriage was done by a clergy member of the Church.
An irregular marriage was not. Irregular marriages were by exchange of
promises before witnesses, by betrothal and consummation, or by cohabitation
and repute, and were forms of marriage recognised by Scots Law, yet may have
taken place without any official record of the event.
In a 'warrant of sheriff substitute' a couple would go to the office of the
local Sheriff (Sheriff-Substitute) with two witnesses. The form of
contract generally adopted was a simple written declaration of acceptance of
each other as husband and wife before two witnesses - and that form was
often drawn up by the Sheriff's office. The Sheriff (or his representative)
would then issue a "warrant" (certification of the marriage) which the
couple would present to the Registrar who would officially record the
marriage and issue a certificate.
Regards.
Monica