I also looking for additional information on the Petty family from Galway.
My GGG grandmother Grace A Petty who was born about 1825 in Castleblakeney Galway.
She married Michael Mitchell Grady. I don't know if they married in Ireland or New York.
She had her first son, Robert George Grady, in New York in 1847. The family moved to Madison, Wisconsin about 1850 and settled in Sioux City, Iowa in about 1870.
Grace A Petty and Michael Mitchell Grady had the following children:
Robert George Grady Sr.(1847 - 1893)
Mary Grady Cary (1849 - 1919)
Eliza Jane Grady Stevers (1853 - 1877)
John M Grady (1854 - 1879)
Rose E. Grady Livingston (1857 - 1931)
William H Grady (1859 - 1885)
Agnes Grace Grady Hutchins (1862 - 1941)
James Henry Grady Sr. (1869 - 1914)
Michael Mitchell Grady Jr. (1869 - 1904)
Stephen D Grady (1880 - 1908)