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A SKETCH OF THE LIAS GENERALLY TN ENGLAND, 



AND OP THE INSECT AND SAURIAN BEDS, 



ESPECIALLY IN THE LOWER DIVISION. 



By the Kev. P. B. BRODIE, M.A., F.G.S,, Vice-President of the Warwick- 

 shire Naturahst's Field Club. 



There are many points of local and general interest in the history of 

 the Lias, both from its wide extent and its abundant and remarkable fossils. 

 Taken as a whole, there is no formation which presents a greater uniformity 

 of Uthological character, so that certain zones in it can be thus as readily 

 distinguished by the practised eye as by their zoological contents, and this 

 especially holds good with regard to the lower portion, which it is proposed 

 more particularly to describe in this paper. Of course, as in every other 

 case, there are local exceptions to this rule, but they are probably less so 

 in the Lias than in any other deposit of equal thickness and importance. 

 A glance at the geological map will show you that its course may be traced 

 from the coast at Lyme in Dorset on the S. W. to Whitby in Yorkshire on 

 the N.E. In the midland counties it is much more expanded, bounded on 

 the west by the New P>,ed Sandstone and on the east by the Oolites, both of 

 which great formations run parallel with it in its range. In Gloucestershire 

 and Somersetshire it sends off many spurs to the N.W., and probably from 

 the effects of extensive denudation from Bristol to Taunton, exhibits many 

 irregularities and numerous outliers, some of which, as in Gloucestershire, 

 Warwickshire, North Staffordshhe, and Cumberland, are of special interest, 

 and present some remarkable features, well deserving, especially in the two 

 last-named counties, of careful examination. 



In order that you may better understand the history of the lower 

 division of the Lias, it will be necessary briefly to describe the entire forma- 

 tion, but I propose, as requested, to dwell more at length on the inferior 

 division so largely developed in Warwickshire, Leicestershire, Gloucestershire, 

 and Somersetshire. This formation has been thus separated into three sub- 

 divisions, viz., the upper, middle, and lower Lias. Such divisions are useful 

 to a certain extent, but may ultimately have to be changed or modified 

 accordinggto future discoveries ; for though many of the organic remains are 

 peculiar not only to these divisions, but some even limited to certain zones, 

 others are common to the whole ; and even the Ammonites, about which so 

 much stress has been laid as marking special zones, may be very possibly found 

 to have a much wider range, and some species indeed which were supposed 

 to characterise particular beds have been since discovered both above and 

 below that zoological horizon. Whatever the ammonites may be, it is certain 



