The Late Precambriam tidal deposits are well developed and widely distributed in North China Platform.The major evidence of tidal sedimentation in these sediments includes herringbone cross bedding

lenticular beding

wavy bedding

flaser bedding

tidal channel-fill cross bedding

reactivation surfaces

various types of ripple marks and interference ripple marks

truncated ripple marks

washout structures

rill marks

mud cracks

and penecontemporaneous deformation structures.In addition

oolites

algae and stromatolites are very significant.The depositional sequences and models of clastic tidal flat

tidal-dominated delta

ferric algal flat and oolitic bank

and carbonate tidal flat(or platform)are discussed here.Four sketch map about these tidal deposits during the early and late Changchen(the Great Wall)

the Jixian

and the Qingbaikou are also given.Finally

it is supposed that these tidal deposits were mainly formed in the epeiric seas on the platform margin.