Just in case you were wondering.......
If your mother's mothers' mothers' etc. etc. etc. mother was Mary Gelder (nee Brown) 1821-1873 then your mitochondria are in Haplogroup J1c3g.
This also applies to any offspring of Jane Brown b. 1814 Luddington, and to any other siblings and their female offspring
So what does it all mean ?
A good, if rather technical, article can be found athttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC3056451/
If that is too much, then start with the basics athttps://customercare.23andme.com/categories/search?utf8=%26%23x2713%3B&query=mitochon drial+dna&for_search=1