辽宁东部地区,大致指长大铁路以东,长白山脉西南的延伸部分,东南隔鸭绿江与朝鲜相望,即包括丹东、本溪、抚顺三市及所辖县。综观这一地区的山势是由东北向西南逐渐降低,山系构成辽河和鸭绿江水系的分水岭。地形是以山地丘陵为主,多由石灰岩、大理岩组成,使形成许多洞穴,为人类生存创造了良好的自然条件。根据这里高程和地形起伏情况,大致可分为两个小区,(1)东北部山地小区,包括长白山支脉,哈达岭和龙岗山的延续部分。在这 The eastern part of Liaoning generally refers to the east of the Chang-Shang Railway and the southwest extension of the Changbai Mountains. The Yalu River across the southeast is opposite North Korea, including the three cities of Dandong, Benxi and Fushun and the counties under their jurisdiction. Looking at the mountains in this area is gradually reduced from northeast to southwest, mountains constitute the watershed of Liaohe and Yalu River. The terrain is dominated by hills and mountains, mostly composed of limestone and marble, so that the formation of many caves, creating a good natural conditions for human survival. According to the ups and downs of elevation and topography, it can be roughly divided into two areas: (1) the mountainous area in the northeast, including the continuation of the Changbai Mountain branch veins, Hatta Ridge and Longgang Mountains. At this