Hidaka Mountains
Geology. The Hidaka Mountains formed in the late Quaternary as part of the outer arc of the western end of the Kuril Island Arc. They were formed by the uplift resulting from the collision with the Kuril arc and the Northeast Japan Arc. The Hidaka mountains no longer appear to be uplifting. The western end of the range is high P/T metamorphoseed Jurassic accretionary complex as part of the Kamuikotan belt. This is characterized by sedimentary rocks from the Cretaceous and Jurassic-Lower Cretaceous periods. The eastern end of the range is tertiary metamorphic rock as part  of the Hidaka Metamorphic belt. This is characterized by low to medium pressure metamorphic rocks with sedimentary rocks from the Cretaceous-Lower Miocene. Plutonic rocks intrude into these structures. For the most part, the Hidaka mountains are composed of schists, migmatites, gneisses, and granites. Glaciation. The Hidaka mountains are the only mountains in Hokkaido to show evidence of glaciation. This occurs above , where one can find moraines and more than 20 cirques from Mount Kitatottabetsu in the north to Mount Toyoni in the south. Flora and fauna. Mount Apoi is known for endemic alpine plant life, such as . The Hidaka  Mountains are also one of the last refuges of the Hokkaido bear ("Ursus arctos yesoensis") and Hokkaido deer ("Cervus nippon yesoensis"). The mountains can be divided into four zones. The topmost zone (1,400–1,600 m) is colonized by Siberian dwarf pine and other alpine flora. From 1,200–1,300 m is occupied by "Betula ermanii". The zone above 500 m is occupied by "Picea jezoensis" and "Abies sachalinensis" along with broad-leafed trees. The lowest zone below 500 m is occupied by broad-leafed trees, including "Quercus mongolica, Acer pictum subsp. mono" and "Cercidiphyllum japonicum". Resident bird species include hazel grouse, black woodpecker , great spotted woodpecker, white-backed woodpecker, goldcrest, Eurasian treecreeper, and spotted nutcracker. Summer visitors to the Hidaka Mountains include Japanese accentor, Siberian blue robin, Japanese robin, red-flanked bluetail, Siberian thrush, Eastern crowned warbler, narcissus flycatcher, blue-and-white flycatcher, dark-sided flycatcher, grey bunting, and Eurasian bullfinch. Notable bird species that transit the Hidaka mountains are Arctic warbler and eyebrowed thrush. List of passes and tunnels. The major passes and tunnels through the Hidaka Mountains are as follows: List of peaks by height. Mountains of the Hidaka range in order of elevation: