Geological Society of London. 125 



official volume is enormous ; and fully ehicidates the structure of 

 tlie largest and most important part of the London district, from 

 near Marlborough to the mouth of the Thames. The Director- 

 General, in passing this work for the press, truly says, " The 

 numerous accounts of well-siukings and borings, given in the 

 Appendix, cannot fail to be of great economic value to many classes 

 of th6 community ; and other questions of geological economics 

 have been carefully attended to. The bibliography of the whole 

 subject, also, in the Appendix, forms a valuable contribution to 

 geological science ; and, indeed, the examination of this Appendix 

 alone attests the extensive knowledge and scrupulous accuracy of 

 Mr. Whitaker." We cordially indorse this well-deserved eulogium ; 

 and we feel assured that all who have recourse to this laborious and 

 conscientious work on the Greensand, Chalk, Thanet beds, Woolwich 

 and Eeading beds, Oldhaven and Blackheath beds, London Clay, 

 Bagshot beds, and " Kentish Crag," of the area under notice, will 

 find themselves aided, as if by a willing and masterful guide. — T.E.J. 



Geological Socibty of London. — I. — Januarys, 1873. — Prof. Eamsay, F.R.S., 

 Vice-President in the Chair. — The following communication was read : — '' The 

 Secondary Rocks of Scotland." — First Paper. By John W. Judd, Esq., F.G.S. 



Introduction. — The Mesozoic periods are in Scotland represented only by a number 

 of isolated patches of strata situated in the Highlands and Western Isles, which 

 have been preserved from the destructive effects of denudation eitlier through having 

 been let down by great faults among the Palaeozoic rocks, or through being sealed up 

 under vast masses of Tertiary lavas. The Cretaceous rocks, exhibiting very interest- 

 ing characters and yielding a beautiful series of fossils, were discovered by the author 

 of the paper during the past year on the mainland and in several of the islands 

 of the west of Scotland. The Jurassic rocks, which were first described by 

 Murchison, are now shown to present a remarkable contrast with their equivalents in 

 England, in being constituted, throughout their whole thickness, by alternations of 

 marine and estuarine series of beds, in which respect they precisely resemble the 

 equivalent strata of Sweden. The Triassic rocks have now been discovered in 

 Sutherland, where their conformable relations to overlying beds containing a fine 

 Liassic fauna, entirely confirms the conclusions concerning their age, derived from 

 Prof. Huxley's studies of the remarkable reptiles yielded by them in Elgin. 



Part I. — Strata of the ^Eastern Coast. — These consist of a number of patches, 

 situated around the shores of the Moray Firth, in the counties of Caithness, Suther- 

 land, Ross, 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 insuSicient ex- 

 amination of the palseontological 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 Reptiliferous Sandstone and the overlying 

 calcareous rocks ; the Rhsetic by conglomerates in Sutherland, and probably else- 

 where 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 Sutlierland, and micaceous sandstones, only preserved 

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

 represented by estuarine beds. 



