1. The results show that : 1 ) though the water environment of nanyisan is more muddy than others, algal can still grow ; 2 ) the composition and rock type of the algal limestone are complex, the main rock types include lettuce - like stromatolites, algal reef, digitate stromatolies, wave - like stromatolites and so on ; 3 ) the deposits of algal limestones were formed in low - energy peritidal to subtidal high - energy environment of lakeshore slopes, sliding under the action of gravity and some other factors and become slump mixosedimentite layers ; 4 ) the physical property of algal limestones layers is better than others ; 5 ) the genetic development of the sediment decides that the single deposit is small, distributive and thin - layed

    2. Mangrove areas are commonly act as nursery grounds for juvenile fishes and other intertidal and subtidal invertebrates

    3. With stromatolite but no desiccation crack, the depositional environment of middle - late cambrian in the area was intertidal zone to subtidal zone with the shallow - water features