赤城山(shan)又稱燒山(shan),在浙(zhe)江天臺西北(bei),為(wei)(wei)天臺山(shan)南門。海拔306.5米,為(wei)(wei)丹霞地貌,是歷代高僧(seng)名(ming)道的(de)修身之處,濟公活佛故里。因(yin)山(shan)上赤石屏列如城,望之如霞,故名(ming)。山(shan)有(you)石洞十二以紫(zi)云(yun)洞和玉京洞最著。山(shan)頂有(you)赤城塔,為(wei)(wei)南朝(chao)梁岳陽王妃所(suo)建。
今“赤(chi)城(cheng)(cheng)棲霞起而建(jian)標”,唐李白《夢游(you)天(tian)(tian)姥吟留(liu)別》詩(shi):“天(tian)(tian)姥連天(tian)(tian)向天(tian)(tian)橫,勢拔五岳掩赤(chi)城(cheng)(cheng)。”《大清(qing)(qing)一統(tong)志.臺州府一.山(shan)(shan)川》:“赤(chi)城(cheng)(cheng)山(shan)(shan),在天(tian)(tian)臺縣(xian)北(bei)六(liu)里(li)。’支遁《天(tian)(tian)臺山(shan)(shan)銘序》:‘住(zhu)天(tian)(tian)臺者,當由赤(chi)城(cheng)(cheng)山(shan)(shan)為道徑。孔靈符《會稽記》:‘赤(chi)城(cheng)(cheng)山(shan)(shan),土(tu)色皆赤(chi),狀似(si)云霞,望之如雉堞。’......舊志,一名燒山(shan)(shan),西有(you)玉(yu)京(jing)洞。道書以為第六(liu)洞天(tian)(tian),名上玉(yu)清(qing)(qing)平之夭,即天(tian)(tian)臺之南(nan)門。”
唐司馬承禎《上清天地宮府(fu)圖經》和杜(du)光庭《洞天福地岳瀆名山記》等道書所據:
第六(liu)赤(chi)城山洞,號“上玉清(qing)平山”(《天地宮府圖》作“上清(qing)玉平之(zhi)洞天),在唐(tang)興(xing)縣(今(jin)浙江天臺)。
赤城山古(gu)稱道教(jiao)十(shi)大洞(dong)(dong)天之六,為一(yi)天然洞(dong)(dong)穴,洞(dong)(dong)深10米,寬7米。洞(dong)(dong)內(nei)隨巖構造三開(kai)間樓(lou)房,周圍植有(you)松柏(bo),鑿有(you)古(gu)井。相傳晉代(dai)魏華存夫人于此棲養修真(zhen),得(de)黃(huang)庭內(nei)外(wai)景二冊自古(gu)號曰黃(huang)庭經,為丹經絕(jue)品。