▁Tr imm ers ▁Rock ▁Form ation ▁( from ▁the ▁Dev onian ▁Period ), ▁the ▁Spe ch ty ▁K opf ▁Form ation ▁( from ▁the ▁Dev onian ▁Period ▁and ▁the ▁Mississ ipp ian ▁Period ), ▁and ▁the ▁On ond aga ▁Form ation ▁( from ▁the ▁Dev onian ▁Period ). ▁All ▁three ▁of ▁these ▁form ations ▁occur ▁in ▁bands ▁that ▁are ▁at ▁an ▁angle ▁relative ▁to ▁the ▁surface . ▁The ▁Spe ch ty ▁K opf ▁Form ation ▁occurs ▁at ▁the ▁peak ▁of ▁the ▁r idge ▁and ▁extends ▁to ▁a ▁depth ▁of ▁approximately ▁ ▁below ▁sea ▁level . ▁The ▁On ond aga ▁Form ation ▁runs ▁from ▁near ▁the ▁r idge ' s ▁peak ▁to ▁ ▁below ▁sea ▁level . ▁The ▁Tr imm ers ▁Rock ▁Form ation ▁runs ▁from ▁the ▁middle ▁elev ations ▁of ▁the ▁r idge ▁to ▁more ▁than ▁ ▁below ▁sea ▁level . ▁Additionally , ▁the ▁M auch ▁Ch unk ▁Form ation ▁is ▁found ▁on ▁the ▁r idge . ▁The ▁sum mit ▁of ▁the ▁r idge ▁consists ▁of ▁hard ▁Po cono ▁Form ation ▁rock . ▁A ▁plain ▁of ▁the ▁Cat sk ill ▁Form ation ▁occurs ▁to ▁the ▁north ▁of ▁the ▁r idge . ▁ ▁There ▁are ▁coal ▁bas ins ▁to ▁the ▁south ▁of ▁N es cope ck ▁Mountain . ▁ ▁During ▁an ▁ice ▁age , ▁gla ci ers ▁pressed ▁against ▁N es cope ck ▁Mountain ▁and ▁eventually ▁moved ▁over ▁it , ▁carrying ▁gra vel ▁from ▁the ▁Sus que h anna ▁River . ▁The ▁r idge ▁was ▁near ▁the ▁southern ▁edge ▁of ▁the ▁most ▁recent ▁period