Based upon observations in the field and on drilling cores，this paper documents the sedimentary features and variations of the Cretaceous System in the Jiaozhou- Laiyang Basin，Shandong province．Several kinds of seismites，including vibrational liquefied sandstone veins， vibrational fractures．vibrational folds and sandy— pillow structure in the lower part of the Laiyang Group，are identified and described in detail． Taking the geological setting of the basin into account，the authors believe that the formation of the Jiaozhou- Laiyang Basin is coeval with the uplifting- extension of the Sulu ultrahigh—pressure terrane．The intensive syn— sedimentary tectonic activity has resulted in the widespread seism ites in the Laiyang Group.