| 释义 |
▪ I. perched, ppl. a.1
(pɜːtʃt, poet. ˈpɜːtʃɪd)
[f. perch v.1 + -ed1 and -ed2.]
1. Seated as a bird upon a perch; set up on a high point; spec. in Geol. applied [after F.] to a block or boulder left resting upon a pinnacle or other narrow support by the melting of the ice which carried it thither; also to blocks left in such a position by other causes; more generally, having an elevation that is exceptionally high in relation to the immediate locality; applied esp. to ground water separated from an underlying saturated zone by an intervening unsaturated zone.
1384–[see perch v.1 3]. 1859–65Page Geol. Terms, Perched Blocks. 1863Lyell Antiq. Man xv. 294 If the glacier is lowered greatly by melting, these circles of large angular fragments, which are called ‘perched blocks’, are left in a singular situation near the top of a steep hill or pinnacle. 1878Huxley Physiogr. 164 Such stones [poised perhaps on the very edge of a precipice, or balanced upon a mere point] known as perched blocks or blocs perchés. 1883R. W. Dixon Mano i. ii. 5 That blinking hood Which in the perched owl's orbs by daylight lies. 1900H. James Little Tour in France (ed. 2) vi. 62 In the matter of position Amboise is certainly supreme in the list of perched places. 1901Bull. Mus. Compar. Zoöl. XXXVIII. 134 (heading) Perched boulders. 1906A. C. Veatch et al. in Prof. Papers U.S. Geol. Survey No. 44. 57 There are..a number of more or less limited areas of saturated beds above the main one. These perched ground-water tables are for the most part confined to the moraine. 1923Water-Supply Papers U.S. Geol. Survey, No. 494. 42 If water poured into the well all drains out the well evidently ends in an unsaturated bed and the overlying ground water is perched. Ibid. 57 The term perched may be applied to streams in the same way as it is applied to ground water. 1956W. Edwards in D. L. Linton Sheffield i. 8 All the igneous rocks are basaltic... Their clayey tops support ‘perched’ water-tables in parts of the limestone uplands. 1968R. W. Fairbridge Encycl. Geomorphol. 740/1 ‘Cirques’..are formed at the heads of glaciers both large and small—including a great many perched, or hanging, glaciers of small dimensions. Ibid. 823/2 (caption) Perched block of Bluff Sandstone.., due to slumping, followed by slope retreat. 1972J. G. Cruickshank Soil Geogr. iii. 84 Any cemented or compacted horizon..can function in the same way and support a perched water table with accumulating soil water.
2. Furnished with a perch or perches:
a. for birds.
b. Of a carriage: cf. perch n.2 1 d.
1671Milton Samson 1692 And as an ev'ning Dragon came, Assailant on the perched roosts,..Of tame villatic Fowl. 1794W. Felton Carriages (1801) I. 57 Coaches and phaetons, either perched or crane-necked.
▪ II. perched, ppl. a.2
see under perch v.2 |