Of the history of the oases during the succeeding seven or eight centuries no records are available, but, judging from the writings of Arabian geographers, between the eleventh and the fifteenth centuries, it is evident that they gradually became depopulated, and were regarded as of little importance. El Sherîf el Edrissi, writing about the middle of the sixth century of the Hegîra, refers to the oases (Al Vahat) as places formerly containing streams of water, with lands on which trees were still found growing, and with ruined, uninhabited towns. He adds that the goats and sheep had become quite wild, and were trapped by hunters like other wild animals. It is not improbable, however, that this author was referring to some of the smaller oases-depressions, such as Kurkur, or perhaps to some of the more outlying parts of Kharga or Dakhla. It seems extremely unlikely, as Hoskins remarks, that the Great Oasis as a whole had become entirely uninhabited. Still later the emir and historian Ismail Abulfida, about the beginning of the fourteenth century, speaks of the oases as abounding with palms and running water, and describes them as situated like islands, in the middle of the desert, three days’ journey from the Said (Upper Egypt). Jacutus describes the positions of three oases, and refers to the first of them as being well cultivated, containing streams and hot springs, palms and cultivated lands. The inhabitants, he adds, are in a wretched state. Several other writers allude to the Egyptian oases, but their information is seldom, if ever, first hand, and the descriptions are in general so vague that we are left in doubt as to which particular oasis their remarks refer. The more modern records, commencing with those of Poncet at the end of the seventeenth century, have already been referred to in a previous chapter. CHAPTER VIII THE EXTINCT LAKES OF THE OASIS Character and Extension of Lacustrine Deposits — Modern Erosion by Wind-borne Sand — The Lakes geologically of Recent Age — Discovery of Pottery and Bones of Domesticated Animals — Area occupied by the Lakes — Maximum Level of their Waters — Lacustrine Strata at Gorn el Gennâh — Relation to the Ancient Monuments — Altitudes of Archæological Sites — Age of the Lakes and their Persistence into Historic Times — Flint Implements — Origin of the Lakes — Their possible connection with the Artesian Waters — Lacustrine Deposits form the Cultivated Lands of Modern Times.