Thanks for the message.The chart which I was given by a Derby descendant has some of the following information -
John Derby 1739-1811 married Mary 1749-1829 and one of his sons was Alexander 1790-1852, who married Mary Ann Hammersley 1793-1877.Their family were Margaret 1830, John 1833-1877, and Sarah 1844-1915, who married Suffern Garvin and lived in Derrygarve, Castledawson (my great grandparents). Sarah was born 25 Apr 1844 in Derrygarve, Castledawson. On the chart there is also a Thomas Derby 1782-1866, who is down as may be a brother of Alexander. Thomas married Sarah Sherman 1785-1863.
Email me at firstname.lastname@example.org with yours and I will keep it on file should I find out more.