10月13日10月13日一大早,考察车队离开龙山县城,取道酉水西岸湖北来凤境内的公路,前往酉水干流穿过的第二个洞穴——卯洞。酉水从宣恩发源地形成地表径流不久,就曾经一头钻进当地称为“猫儿孔”的洞穴,以地下河的形式穿过大山,再从白水洞出来。酉水流经的武陵山区属喀斯特地形,洞穴成群,阴河遍布,一 October 13 On the early of October 13, on the morning of October 13, the fleet was inspected for leaving the Yongsan county seat and taking the highway in western Laifeng in the west coast of Hubei Province to the second caves, the Mao-dong, through which the mainstream of the Yushui River passes. Not long after the surface runoff formed from the source of Xuan’en, we once went into the cave called “Cat Hole”, crossed the mountain in the form of an underground river and then came out of Baishuidong. Wuling Mountain flows through the Wushan terrain, caves, Yin He all over, one