Internal-wave and internal-tide deposits of the third member of lower Cambrian Balang Formation at Yangjiaping, Shimen, Hunan Province, China

The third member of the lower Cambrian Balang Formation at Yangjiaping, Hunan province, China consists mainly of gray, dark-gray laminated to thinly bedded silt-bearing mudstones and muddy siltstones interbedded with lenticular siltstones. Cross laminations are well developed in siltstones of the middle and upper of the third member, whose laminae inclined not only bi-directionally which correspond to up- and down-slope directions, but also uni-directionally which correspond to up- or down-slope directions. The characteristics indicated that lenticular siltstones should be formed by alternating up- and down-slope currents produced by internal waves and internal tides.