广西横县六景泥盆系剖面在国内外素有盛名。中、下泥盆统之间的界线,因其间有厚约184米的白云岩,长期未找到确切的古生物证据,以致各家划分意见不一。1975年后,虽找到了牙形刺群,证明那叫组为跨统的岩性组,但一直未找到大化石。 Guangxi Hengxian six sections of Devonian profile known at home and abroad. The boundary between the Middle and Lower Devonian was divided due to the fact that no dolomite of about 184 meters in thickness was found between them for a long period of time without any accurate paleontological evidence being found. After 1975, although it has found a conodonts to prove that the group is a lithological group across the system, but has not found a large fossil.