As an adjective, the word appears to be originally American.
1802. A baker in this city offers Mammoth bread for sale. We suppose that his gigantic loaves were baked at a Salt Lick, and perhaps may form a great rock bridge, or natural arch, between the mouth and maw of a voracious republican.—The Port Folio, ii. 31. [The allusion is to Jefferson’s writings, and to the “Mammoth Cheese” which had recently been sent to him at Washington.]
1802. No more to do with the subject, than the man in the moon has to do with the mammoth cheese.—The Balance, Hudson, N.Y., Oct. 19, p. 331/1.
1803. I know not the weight of the “greatest cheese in the world,” but it was I believe equal in circumference to the hindmost wheel of a waggon. Its extraordinary dimensions induced some wicked wag of a federalist to call it the Mammoth Cheese; and by this name it is known throughout the States of the Union.—John Davis, ‘Travels in the U.S.A.,’ pp. 329–30 (Lond.). (Italics in the original.)
1805. A Mammoth Pear is described in The Balance, Dec. 3, p. 387/3.
1812. “The Mammoth Horse, Columbus,” to be seen at Roulstone’s Riding School.—Boston-Gazette, Sept. 21.
1818. Family pie is, in the New England dialect, nearly synonymous with mammoth pie.—Mass. Spy, Oct. 7: from the Columbia Centinel.
1824. The last load, as we Yankees say, was a “Mammoth”:…. producing an aggregate of nearly twelve cords.—Mass. Spy, Jan. 14.
1824. “A Mammoth Egg,” described in the Western Carolinian: Carolina Gazette, Feb. 14, p. 1/3.
1837. Not long since the papers were full of articles for and against the Mammoth Bank; now mammoth pumpkins are all the go.—Balt. Comml. Transcript, Oct. 23, p. 2/1.
