Green’s Dictionary of Slang

corncob n.

(Aus.) a countryman, a peasant.

1889		Dly Bulletin (Honolulu, HI) 2 Nov. 3/4: Jabez Corncobb Esq. ‘believed the whole Opposition would evaporate’ [...] Rev. Dr Dryhash was of the opinion that ‘if a serious revolt happened that it would not matter’.
1890		‘Rolf Boldrewood’ Colonial Reformer III 165: Right you are, old corn-cob.
1910		Bulletin (Sydney) 6 Oct. 32: Corncob (discussing the new schoolmistress): ‘Well, ye sez yer fair shook on her; and ’ere ye ’ave yer 320 acres, a four-roomed ’ouse, and 70 cows.’.
1915		Meade Co. News (KS) 26 Aug. 6/6: Mr Corncobbe, I dare say your son has learned a great many things at college.

In compounds

corncob aristocracy

(US) a wealthy farmer.

1853		Life in Boston & N.Y. (Boston, MA) 8 Oct. n.p.: A class of corn cob aristocracy who live in this township [...] Prosperity crownded their heads for many years.
1908		Guthrie Dly Leader (OK) 11 Sept. 1/5: [headline] Corcob Aristocracy Can Afford Automobiles.
1990		York Sun. News (PA) 2 Dec. 3G/5: There have been wonderful parties when I have gathered other scions of that corncob aristocracy.