Cretaceous seas can be shallow.Logical formLearned from1 sentences. A cretaceous system may pertain-to the south.Logical formLearned from1 sentences. A cretaceous system may fall into some divisions.Logical formLearned from1 sentences. A cretaceous system may contain a diversity of types of sediment.Logical formLearned from1 sentences. A cretaceous system can be as a whole.Logical formLearned from1 sentences. Cretaceous system can be in a system.Logical formLearned from1 sentences. Foothills can be cretaceous.Logical formLearned from1 sentences. Synclines can be cretaceous.Logical formLearned from1 sentences. Zones can be constituted-of-or-filled-with cretaceous limestone.Logical formLearned from1 sentences. Zones of cretaceous limestone may be joined by a strip of formations.Logical formLearned from1 sentences. A (region commencement) may pertain-to a cretaceous period.Logical formLearned from1 sentences. An end of a cretaceous period may see a beginning of a series of (earth movements).Logical formLearned from1 sentences. A division can be between cretaceous periods.Logical formLearned from1 sentences. An order can be cretaceous.Logical formLearned from1 sentences. A (tailless pterosaur) may pertain-to a cretaceous period.Logical formLearned from1 sentences.