What documentation do you have for Leonard being the son of Jerusha Griswold and Samuel Buell, who are my 4th great grandparents. In family histories compiled by Albert Welles (1881), Elias Buell(1870) and Nathan D. Buell (1985), Leonard Buell is not shown as a son of Jerusha and Samuel Buell. Elias' brother Samuel was also part of the 1847 wagon train to Oregon,
In a 15 Feb 2009 newpaper article in The News-Review, descendents of Leonard and Julian Ann (Giles) Buell were quoted as claiming Leonard came to Oregon in 1847 as a brother of the Elias Buell, but Elias did not list Leonard as being part of the wagon train. I do not find Leonard in Oregon records until 1852.
Samuel and Jerusha moved to Benton Center, Yates Co NY, which is roughly 80 miles from Genesee County. The family histories show Samuel and Jerusha had son Samuel in 1811 and daughter Amy in 1817, both in Benton Yates Co. NY. While I am always happy to locate cousins, it seems unlikely to me that having been settled in Benton Center since 1792, that Samuel and Jerusha would have had a baby in Genesee county in 1814, when all of their other children were born in Yates Co.
The 1870 census for California lists Leonard Buell, age 55, born in Vermont, living with wife Jula A., and children Orson, Sylvester, Peter, Almond, Julia and Mary. If Vermont is correct, there is no direct connection to the Samuel and Jerusha Buell family.