I'm not related to this Carter family, but I found this searching here on Ancestry.com. It's a marriage record from Indiana for Obediah Blakesley and Harriett Carter: 27 Mar 1828.

http://search.ancestry.com/cgi-bin/sse.dll?rank=1&new=1&...

You might be able to contact the Vermillion County, Indiana courthouse and obtain a copy of the marriage license.

Also found this record below at findagrave.com, which lists a Harriet Blakesley buried in Taylor County, Iowa at Fairview Cemetery:

Birth: unknown
Death: Jul. 29, 1882
Aged 74y 7m
Burial:
Fairview Cemetery
Lenox
Taylor County
Iowa, USA

http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=Bl...;

And this census record from 1850. There's also one I found quickly from 1860:
http://search.ancestry.com/cgi-bin/sse.dll?rank=1&new=1&...

I hope this helps!