Hi Lorica
I presume this is an ancestral line from Isabella back to John?
What additional information are you looking for? Do you want to go forward or back or look at siblings? Do you have them on the 1841-1901 censuses? This would give information about their occupations and children, etc.
The marriage certificate of Angus to Mary Ann would give his mother's name and thus the wife of Angus (b. 1834) and, if this Angus married in 1855 or after, his marriage cert would give his mother's name and thus the wife of John. Similarly, with Isabella's and Angus, jnr.'s birth certs and John's death cert.
These BMDs and censuses can be found on the Scotlands People site
www.scotlandspeople.gov.uk It's a pay to view site but very reasonable - e.g. an index search and a view/download of a copy of a cert. would be 6 credits (=£1.20)
Regards
Gadget