[Footnote 138: For the city and pass of Derbend, see D'Herbelot,
(Bibliot. Orient. p. 157, 291, 807,) Petit de la Croix. (Hist.
de Gengiscan, l. iv. c. 9,) Histoire Genealogique des Tatars,
(tom. i. p. 120,) Olearius, (Voyage en Perse, p. 1039 - 1041,)
and Corneille le Bruyn, (Voyages, tom. i. p. 146, 147:) his view
may be compared with the plan of Olearius, who judges the wall to
be of shells and gravel hardened by time.]