Hi Al,
Glad that Isabella CRICHTON other name SINCLAIR who died in 1868 aged 66 was yours and that I didn't send you off wasting your credits!
Somewhere in this thread, you seemed to indicate that you didn't have the marriage date of James SINCLAIR and Martha JACK. It's in the IGI. The following are all extracted entries, all in Eassie & Nevay.
James SINCLAIR m Martha JACK 15 Aug 1795
They had:
*Isobel SINCLAIR bap 16 Aug 1796 (Isabella's age understated at her death, but correct in the 1851 census - where she was 54 and born Eassie)
*Margret SINCLAIR bap 1 May 1798
*John SINCLAIR b 18 Jun, bap 22 Jun 1800
*Ann SINCLAIR b 14 Dec, bap 19 Dec 1802
*Alexander SINCLAIR b 14 Mar, bap 17 Mar 1805
I hope that the Helen JACKSON, other name SCOTT, who died in 1880 aged 79 is also yours!
The following are all extracted entries from the IGI, all in Dundee.
James JACKSON m Helen SCOTT 15 Dec 1827
They had:
Thomas JACKSON b 29 Feb, bap 16 Mar 1828
James JACKSON b 25 Nov, bap 5 Dec 1830
Barbara Scott JACKSON b 11 Mar, bap 25 Mar 1832
Matilda Sturrock JACKSON b 25 Apr, bap 13 May 1834
Janet JACKSON b 8 Jun, bap 3 Jul 1836
There are submitted entries in the IGI for Helen SCOTT's baptism (3 Dec 1800, parents James SCOTT and Elizabeth IRELAND) in Murroes (her birthplace according to the 1851 census where her age is given as 50). The submission looks pretty reliable.
James SCOTT and Elizabeth IRELAND had in Murroes (extracted entries):
John SCOTT bap 6 Sep 1795
Barbara SCOTT bap 11 Jul 1809
Matilda SCOTT bap 1 Mar 1812
(There are also submitted entries for the following James 1791, Agnes 1793, Helen 1800, David 1805)
It seems that Helen (SCOTT) JACKSON named two of her children after her sisters. - Barbara and Matilda are not particularly common names.
In the IGI there's a marriage (extracted) of a Matilda SCOTT to a Peter STURROCK, 13 Sep 1831, Dundee. At least this explains your Matilda's middle name of Sturrock! The IGI has this couple having a Matilda b 1833 Dundee, and a Peter bap 1834 Liff.
The family is in the 1841 census on FreeCEN - Peter STURROCK 30 Weaver, Matilda 28 Dressmaker, Matilda 8, Peter 6, John 4.
I tried to find the death of Martha (JACK) SINCLAIR on the SP free search but without success. There is one Martha SINCLAIR of an appropriate age who died in 1855 but whether this is Martha JACK or a different Martha SINCLAIR I don't know. Your Martha (77 in 1851) might well have died between the 1851 census and the start of Statutory Registration in 1855.
JAP
PS: A search for Eassie in Google Images brings up some interesting hits.