258 ME. s. s. BUCKMAX o?^ [vol. Ixxui, 



The classical paper on the Scottish area is that hy J. W. Judd.^ 

 He proposed the terms ' Scalpa Sandstone ' and ' Pabba Shales,' 

 and, though working under great difficult}^ showed considerable 

 acumen in his zonal classification: he recognized the presence of 

 the zones of humphriesicDium, miirchisonce, sjnnaius, margari- 

 tatus, ibex, jamesoni, armatus, oxynotus, sonicostatus, and 

 hucMandi. 



A more elaborate faunal sequence is put forward at the present 

 day, as shown by various chronological lists which have been 

 published by the present writer, for instance : — 



1898. ' Jurassic Time ' Q. J. G. S. vol. liv, p. 442. 



1901. ' Horn. Brach.' Proc. Cotteswold F. C. vol. xiii (4), App. II, p. 265. 

 1910. ' Jurassic Strata ' Q. J. G. S. vol. Ixvi, p. 86. 

 1910-13. ' Yorkshire Type Ammonites ' i, p. xvi; ii, p. x. 

 1915. 'Pal. Class. Jur. Rocks ' ; 'Geol. Whitby' 2nd ed. Mem. Geol. Surv. 

 1915, chap. V, p. 60. 



The tables in the two last-named publications may be taken 

 as a basis of reference. But the excellent results obtained by 

 Mr. W. D. Lang. 2 b}^ most painstaking work on the Dorset Coast, 

 show that still further elaboration is required. The same is the 

 lesson taught by the Scottish deposits. I propose to illustrate 

 and compare these results Avith each other, and with details from 

 intermediate areas. 



The present paper is entitled ' I — Lias ' to indicate that it is the 

 first of a proposed series, to be followed, I hope, by further papers 

 on the Oolites so as to complete the Jurassic Chronology on the 

 same lines. The present paper gives the information about the 

 Lias by working downwards from younger to older deposits, because 

 that presents the different sections of the strata in continuous orderly 

 sequence. Strictly speaking, then, this series of papers should 

 have commenced with the latest rocks of the Jurassic ; but, as I 

 am not prepared mth their details, the sequence in the pajDers and 

 that in the series must remain at A^ariance — a technical blemish. 



One could Avish that, for geological and other records, printing 

 and reading were from the bottom of the page to the top, because 

 then results could be placed in their due order of developmental 

 sequence. 



For stratigraphicai information, pala?ontological material, and 

 generous assistance, I am Axry greatly indebted to several kind 

 friends : for Scotland, to Dr. G-. W. Lee and other officers of the 

 Greological Survey, Scotland; for Yorkshire, to Dr. F. L. Kitchin, 

 Mr. G. W. Lamplugh, Mr. Gr. BarroAv, and other officers of the 

 G-eological Survey, England ; for the Midlands, to Mr. B. Thomp- 

 son ; for Somerset and Grloucestershire, to Mr. J. W. Tutcher ; for 

 the Dorset Coast, to Mr. W. D. Lang ; for varied information, to 



^ ' The Secondary Eocks of Scotland ' (West Coast), Q. J. G. S. vol. xxxiv 

 (1878) p. 660. 



2 Proc. Geol. Assoc, vol. xxv (1914) p. Ii93. 



