黑岩穿洞是连接凤梧镇与龙眼镇两镇的交通要道，入口处多为被化学沉积物所包裹崩塌堆积物，出口处多为具有明显的向光性钟乳石。洞内的石笋、石柱和沿裂隙生长的石钟乳等次生化学沉积物已出现白化、黑化现象。洞内篆刻“獐地灵岩”的黑岩石碑，为县级保护文物。 The Heiyan light-through cavity is the main traffic artery connecting Fengwu town and Longyan town. At the entrance, there are mainly collapsed deposits covered by chemical sediments, and at the exit, there are many heliotropic stalactites. The secondary chemical deposits such as stalagmites, stone pillars and stalactites growing along the fissures had appeared whitened and blackened. In the cave, there is also a Heiyan monument inscribed with Chinese characters “Zhang Di Ling Yan”, it is a cultural relic under the county level protection.