The lower part formed in a littoral-epeiric environment, is a series of elastic rocks, partly contains carbonate rock an其下部为一套滨浅相碎屑岩，局部夹碳酸盐岩、变质基性火山岩；上部为一套深水沉积岩系夹硅质岩，局部夹变质基性火山岩。