The Upper Permian bioherms of Guizhou are composed of the remains ofvarious kinds of sponges and siphonoconchs which are haphazardly distribu-ted in micrite matrix.Organisms are usually surrounded by lime muds whichform agate-like stripes or bands but bear no relation to algae.Lime mudsare all chemical precipitates deposited during diagenesis.They form calcitesof different morphology(microcrystalline

fibrous

comb-like and poikilitic)

which do not merely occur as crusts enclosing organisms but also fill theirregular voids.The sponges

attacked constantly by violent waves

are continuously bo-ring and destroying the substrate of carbonate rocks and at the same timeproviding various peculiar pores for sponges to live in

for sedimentationand cementation

and thereby a unique framework is formed.Any of theseprocesses may follow earlier ones

thus forming bioherms or edgewise organicmounds distinct from general frame work reefs.In this paper

the Late Permian of Guizhou is divided into the fluvial

delta-plain

subaqueous delta

inner-continental shelf(carbonates)

outer-continental shelf(tuffaceous clastic and siliceous sediments)facies.Biohermsare only distributed at the contact zone between the inner and outer conti-nental shelf facies;along this zone

bioherms can be traced discontinuously.The reef zone within the territory of Guizhou generally stretches in a NEE direction

only the section between Ceheng and Wangmo being locally com-plicated.The section occurs as an appendix bulging northwards

thus cre-ating a false impression that there are“two rows”in local places.The distribution of the reef zone is controlled by sedimentary environmentsand processes rather than by anticlines.Wherever the reef zone runs by

its traces should be left whether on anticlines or on synclines.Its exposureon anticlines is only a superficial phenomenon.