naturalization record from Oct 1850 for THomas O'Leary (1817-18980

My 4th GGrandfather came from Ireland. According to voter registration records in California, he was naturalized in Montgomery County in 1850, his declaration of intent was filed June 1, 1847 in Mohawk Valley, Herkimer, NY at age 21. I cannot find any documentation for this information. The naturalization records are not found in the New York court system as far as I can tell from California checking online.

Of note, I have him arriving in San Francisco on the steamer Oregon in 11 Feb 1852. He became a gold miner in Yuba County. He married Bridget Quigley on 7 Jan 1858 at Mission San Jose in Fremont California.

Can anyone give me advice or assist? Thank you.
Maryann Campbell Castaneda