, ▁the ▁National ist ▁government ▁began ▁building ▁the ▁Central ▁Cross - Is land ▁Highway ▁between ▁ 1 9 5 6 ▁and ▁ 1 9 6 0 . ▁Chi ang ▁K ai - she k ▁visited ▁the ▁pass ▁in ▁ 1 9 5 8 , ▁ren aming ▁the ▁site ▁as ▁" Day uling " ▁after ▁the ▁story ▁of ▁Great ▁Flo od ▁of ▁Gun - Y u ▁( G un - Y u ▁is ▁altern atively ▁known ▁as ▁Day u ) ▁as ▁a ▁reference ▁to ▁the ▁difficult ▁construction . ▁ ▁Ge ology ▁ ▁Day uling ▁is ▁located ▁within ▁a ▁str atum ▁known ▁as ▁the ▁Day uling ▁Form ation ▁( 大 <0xE7> <0xA6> <0xB9> <0xE5> <0xB6> <0xBA> <0xE5> <0xB1> <0xA4> ), ▁a ▁subset ▁of ▁the ▁Bil u ▁Form ation ▁( <0xE7> <0x95> <0xA2> <0xE7> <0xA5> <0xBF> 山 <0xE5> <0xB1> <0xA4> ). ▁The ▁str atum ▁was ▁first ▁identified ▁by ▁ge ologist ▁Z ha ox ia ▁Chen ▁( 陳 <0xE8> <0x82> <0x87> 夏 ) ▁in ▁ 1 9 7 9 . ▁The ▁ 2 , 2 0 0   meter ▁thick ▁layer ▁is ▁composed ▁of ▁sl ate , ▁ph yll ite , ▁and ▁quart z ite . ▁Num mul ite ▁foss ils ▁were ▁found ▁near ▁Day uling , ▁the ▁first ▁in ▁Taiwan . ▁Due ▁to ▁the ▁fol iation ▁of ▁the ▁rock , ▁the ▁construction ▁of ▁He hu ans han ▁T unnel ▁at ▁Day uling ▁proved ▁to ▁be ▁difficult ▁and ▁pr one ▁to ▁collapse . ▁ ▁References ▁ ▁Category : Mount ain ▁passes ▁of ▁Taiwan ▁Category : Land forms