The great trade centres of Turkistan, north of the Paropamisus, in mediæval days were undoubtedly near Panjdeh, at the confluence of the Kushk and Murghab rivers, and at Merv-el-Rud, or Maruchak. Two or three obvious routes lead from the passes above Kaman-i-Bihist, or above Herat, to Panjdeh and Maruchak. One is indicated by the drainage of the Kushk River, and the other by that of the Kashan, which is more or less parallel to the Kushk to the east of it, with desolate Chol country in between. From Herat the most direct route to Panjdeh and Merv is by the Babar Pass, or by Korokh, the Zirmast Pass, and Naratu. Korokh (Karuj) is mentioned both by Ibn Haukel and Idrisi as being situated three marches from Herat, surrounded by entrenchments, and in the "gorge of mountains," with gardens and orchards and vines. The Korokh of to-day is between the mountains, but only some twenty-five miles from Herat. This modern Korokh has, however, many evidences of great antiquity, and it is on the high-road to an important group of passes leading past Naratu to Bala Murghab and Maruchak. The most remarkable feature about Korokh is a grove of pine trees closely resembling the "stone" pine of Italy, which mass themselves into a dark blotch on the landscape and mark Korokh in this treeless country most conspicuously. There are no other trees of the same sort to be found now in this part of Asia, but I was told that they once were abundant in the Herat valley, which renders it possible that the "arar" trees, mentioned by Ibn Haukel as a peculiar source of revenue to Bousik, may have been of this species. Naratu, again, is very ancient, and its position among the hills (for it is a hill-fortress) seems to identify it with Dahertan. Undoubtedly this was one of the most important of the old routes northward, and it is a route of which account should be taken to-day.