Mr. J. W. J add on the Secondary Rucks of Scotland. 3.27 



af the Moray Firth, in the counties of Caithness, Sutherland, ltoss, 

 Cromarty, and Elgin. The preservation of these is shown to be 

 entirely due to the operation of faults of enormous magnitude, which 

 have let down the Mesozoic strata against the various Palaeozoic 

 rocks. Owing to an insufficient examination of the palaeontological 

 evidence, much misconception has hitherto prevailed concerning the 

 geological age of most of these patches ; but a careful study of their 

 faunas enables us to reconstruct an almost unbroken history of the 

 Triassic and Jurassic periods in the north of Scotland ; while even 

 concerning the Cretaceous much important evidence is afforded by 

 the boulders, which abound in the drifts. 



The Keuper is represented by the Eeptiliferous Sandstone and the 

 overlying calcareous rocks; the Ehaatic by conglomerates in Suther- 

 land, and probably elsewhere by estuarine beds, which are now, 

 however, only preserved in great boulders. 



The Lower Lias is constituted in its lower part by a thick series 

 of estuarine beds, sandstones, shales and coals (hitherto referred to 

 the Lower Oolites), and in its upper part by marine strata yielding 

 a highly characteristic fauna. The Middle Lias is formed of clays 

 seen in situ in Sutherland, and micaceous sandstones, only preserved 

 in boulders ; both furnish very fine series of fossils. The Upper 

 Lias is probably represented by estuarine beds. 



The Lower Oolites are almost wholly made up of estuarine strata, 

 containing coal-seams, which have been frequently worked in the 

 past in mines which are now being reopened. The beds yield many 

 freshwater fossils, which have attracted much attention, owing to 

 the general resemblance they present to those of the Wealden. 



Of the Middle Oolites we have a wonderfully complete series in 

 the east of Scotland. At the base is a calcareous sandstone crowded 

 with Kelloway fossils ; above this 300 feet of shales, yielding the 

 well-known Ammonites and other fossils of the " Ornatus-clays " 

 (Middle Oxfordian) ; still higher are beds of marine sandstone with 

 a magnificent fauna, identical with that of our Lower Calcareous 

 Grit. A thickness of 400 feet of estuarine sandstones <fec, which 

 covers the last, is surmounted by limestones, shales, and sandstones, 

 with the fossils of the Coral Eag. 



The Upper Oolites, now for the first time recognized in Scotland, 

 are of great thickness, and consist of alternations of estuarine and 

 marine strata, yielding a splended fauna and flora. In their northern 

 extension these beds pass into the wonderful " brecciated beds " of 

 the'Ord, which contain enormous transported blocks of Old Eed 

 Sandstone. The features presented by these strata are of the highest 

 interest, and are very suggestive of the prevalence of peculiar phy- 

 sical conditions in the area towards the close of the Jurassic period. 



The patches of Secondary strata on the coasts of Eoss, usually 

 called Lias, are shown to belong to the Lower, Middle, and Upper 

 Oolites ; and a mass on the coast of Elgin is demonstrated to be also 

 of Oolitic age. 



In future papers the author proposes to describe the Secondary 

 rocks of the west coast and islands of Scotland, and to discuss the 



