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1864 J. von Haast Rep. Form. Canterbury Plains 19 Thinking that giving such a name [sc. ‘delta’] to the alluvial accumulations of the rivers in this island, showing some peculiarities, would impart an erroneous impression, Dr. Hector and myself, in drawing up a synopsis of the geological formations of New Zealand, have adopted for the formation of those subaerial accumulations the expression ‘Fan’, for those of regular water-courses; and of ‘Half-cone’, for those of intermittent mountain torrents, and we shall for the future use these two expressions.

1873 Q. Jrnl. Geol. Soc. 29 446 At the mouth of each of these [gorges] are alluvial fans, which project out into the flat of the river-alluvium.

1873 Q. Jrnl. Geol. Soc. 29 447 The fan is properly a flat cone, having its apex at the mouth of the ravine.

1883 Proc. Royal Physical Soc. Edinb. 7 290 In this paper lateral delta terraces will be referred to as fan terraces.

1884 Dawson in Leisure Hour Aug. 492/1 A great mass of similar matter was projected from it in a fan or delta.

1890 Gilbert in U.S. Geol. Surv. Monogr. I. 81 The ‘alluvial fan’ of Drew is the ‘alluvial cone’ of American Geologists, and there would be some reason for preferring ‘fan’ to ‘cone’ if it were necessary to employ a single term only. It is convenient to use them as synonyms, employing ‘cone’ when the angle of slope is high and ‘fan’ when it is low.

1902 in Ld. Avebury Scenery of Eng. 482 The vale of Neath contains a series of such cones or ‘fans’ of gravel.

1920 Nature 13 May 322/2 The wind-worn grains of magnetite brought northward from the great fan-deltas of the Adour system.

1948 Proc. Prehistoric Soc. 14 34 These alluvial fans extend right down to the sea.

1965 A. Holmes Princ. Physical Geol. (rev. ed.) xviii. 551 There are all gradations from wide fans 10–100 miles across that are usually nearly flat.., through fans of moderate width and inclination.., to relatively small steep-sided cones..built of the coarser debris brought down by short torrential streams.