Sentence:  If this view be correct there must have been a great difference in the sedimentation of the two areas, as the thick beds consist of alternations of <WSD>flaggy</WSD> sandstone with occasional true sandstone, almost pure limestones, calmstones, and few or no real flagstones. 
Meaning of the word marked with <WSD> tags:  Tending to split into layers like flagstones.