There is a mountain range separating Harir Plains from Alana Sun, the Xalifan gorge, and the Rawanduz gorge -- and its one pass is at Spilik.
If you look at the map of the Rowanduz district you will see that this pass is the only one that leads over the Harir Dagh and that it commands the way to Turkey and Persia. Like a portcullis the range [of the Harir Dagh] shuts the highlands of Rawanduz off from the lowlands, and only at Spilik where the ridge drops below four thousand feet could the merchant traffic find a way. The caravan track winds up beside a deep abyss on the steep mountain-side, among great boulders higher than a standing man. Spilik Pass had always been the home of robbers and brigands. For many centuries travelers had come and gone by this road, and in consequence the brigand chieftains had flourished merrily, as became Kurdish gentlemen. Hamilton, p 59; edited for brevity
There is a steep zigzag ascent known as the Spilik pass to the limestone mountains of Central Kurdistan; it is more in the nature of a big step up to a corrugated plateau seamed with valleys and gorges. From here the Turkish cart road descends a side valley to the Khalifan stream and enters the gorge at Gali Ali Beg. Mason 1919, p 333
Mason, Kenneth. 1919. Central Kurdistan, The Geographical Journal, Vol LIV No 6. http://www.jstor.org/stable/1779409