Hello Lynn,
Apologies if I state the obvious.
Any direct line family member must be traced if possible back through the census records from just before death - in your case from the 1871 one back to the 1841 at 10 yearly intervals.
I note on the government website at 
www.scotlandspeople.gov.uk that there is a 3 page will for 'your' Thomas.  May refer to some siblings?  Cost £5.00 using a 'cart' system.  I did not look to see if James left a will.
CARRICK   THOMAS   01/04/1874   COOPER, RESIDING AT # 129 HIGH STREET, DUMBARTON, WINDOW MRS ELIZABETH CAMPBELL OR CARRICK       DUMBARTON SHERIFF COURT   SC65/34/1
Shall go and look for other siblings.  A polite reminder also that the info on the death entry is only as good as the person who supplied its knowledge.  If it wa shis wife or a sibling it should be reasonably reliable.
Regards,  Steve    
