Jonathon and Zenos G. (not C) Coolidge are brothers.They both were living in Delaware Co., Iowa at the time of the 1856 Iowa state census.
Jona(h) Brigham Cooli(e)dge and Sally Graves were the parents of the following children:
Danial born March 17, 1815 in NY Jonathon S. born January 26, 1817 NY Lyman B. born 1819 Aurelios, Cayuga Co., NY Leornard born 1820 NY Ann L. born October 13, 1826 NY Jonas L. born 1828 NY Zenos G. born August 28, 1830 Desdamona M. born February 5, 1835 NY
They all died in Delaware Co., Iowa.Near the town of Yankee Settlement, now named Edgewood. I don't have a place or date of death for Jonas altho I think he died close to Edgewood.
I have a little more info on each of these, if anyone is interested.