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Summary The Scalpa Sandstone of Raasay is 405 feet thick, and it ranges from the middle of the Ibex Zone of the Lower Lias to the lower part of the Tenuicostatum Zone of the Upper Lias. The Lower Liassic part contains rare representatives of Liparoceratid ammonites, and these give some indication of the subzonal divisions. The Middle Liassic part yields an abundance of Amaltheid ammonites except in the lowest beds, and precise zones and subzones have been recognized. The two zones of the Middle Lias, the Margaritatus and Spinatum Zones, are 140 and 134 feet thick respectively. The Amaltheids and sediments of the Margaritatus Zone do not differ widely from those of this zone on the Yorkshire and Dorset coasts. The sediments and thickness of the Spinatum Zone are totally different from those in Yorkshire and Dorset, and the Amaltheids are almost completely different from those in the Yorkshire Spinatum Zone, but show some resemblances to those of Dorset, and contain other elements peculiar to Raasay. The Upper Liassic part is only 6 feet thick and contains a few Dactylioceratids. Stratigraphical records of a considerable number of brachiopods are included in the detailed section.

Summary The two zones of the Middle Lias of the Dorset coast are remarkably different. The spinatum Zone at the top has a maximum thickness of only two feef, consisting of ferruginous sandstones or limestones containing species of Pleuroceras . The margaritatus Zone is more than two hundred times thick, consisting of loams, clays and sands, wit hard sandstone and limestone bands, containing species of Amaltheus and Amauroceras . In the palaeontological section of the paper, remarks on the amaltheid ammonites are confined to their stratigraphical distribution, and more detailed treatment is given to representatives of Metacymbites, Dactylioceras , and the Middle Liassic hildoceratids Leptaleoceras and Paltarpites . Finally, a comparison is made with the stratigraphy and ammonite faunas of the Middle Lias on the Yorkshire coast, and the conclusion is drawn that differences between the two areas were greater in spinatum Zone times than in margaritatus Zone times.