horstn.

1893 Q. Jrnl. Geol. Soc. 49 77 We have, therefore, sunken massifs both west and east of the Dürrenstein; that mountain itself remains at a higher level between the two, and may be called a ‘Horst’ in the sense originally applied by Suess.

1904 H. B. C. Sollas & W. J. Sollas tr. E. Suess Face of Earth I. i. iii. 126 If the outer borders of two fields of subsidence approach each other so that a ridge is left between them, on both sides of which the two areas of depression descend more or less in the form of steps, then we have what we shall distinguish, making use again of a common mining word, as a horst.

1910 Encycl. Brit. X. 598/1 Crust~blocks resembling ‘graben’ and ‘horsts’.

1914 G. A. J. Cole Growth of Europe ii. 22 Far older masses have asserted themselves..as horsts, that is, as upstanding blocks from which material has been faulted down on all sides.

1942 M. P. Billings Struct. Geol. xi. 205 Horsts range in size from those that are only a few inches wide to those that are many miles wide.

1944 A. Holmes Princ. Physical Geol. xix. 416 Between the horsts of the Vosges and the Black Forest the Rhine flows through a rift valley.

1970 Sci. Amer. Feb. 37/3 The evidences of crustal movement are in plain view as wide-open fissures, horsts and grabens that form a classic graben structure of steps down the sides of a major depression.