Charles Lapivorth. 



XXXlll 



stratigraphy. His magnificent paper on the ' Distribution of the Khab- 

 dophora' came like a revelation to his co-workers, so many unexpected 

 results did it disclose, and so thoroughly had Lapworth realised his dream of 

 zoning Lower Palaeozoic rocks, not merely as satisfactorily as had been done 

 for the Neozoic rocks, but, in truth, far more so. For these zones are more 

 constant over wide areas than are those in newer rocks, the reason, worked 

 out by Lapworth, being that the graptolites were pseudo-planktonic in 

 habit; attaching themselves to seaweeds, they were drifted right over the 

 seas, and became embedded in the fine sediments deposited in the ocean 

 depths. 



The influence of this research upon contemporary work is shown in the 

 ' Monograph of British Graptolites ' by Miss Elles and Miss Wood, written 

 for the Pala^ontographical Society under Lapworth's editorship, in which the 

 Lower Palteozoic zones are shown to have increased from 20 to 36, and 

 the number of species dealt with from 284 to 372. The graptolites were 

 also made to yield their contribution to the study of evolution ; the minute 

 variations exhibited by the species in ascending sequences, which in the 

 first instance were observed for their geological bearing, being evidently 

 directed towards improved conditions of life and promoting the survival of 

 the fit. 



Lapworth's third piece of work relates to the ancient rocks of the 

 Midlands, beginning in 1881, the date of his appointment as Professor at 

 Birmingham. The Ordovician rocks of Shropshire were studied in detail, 

 and paralleled with those of Scotland and elsewhere. The Upper and 

 Middle Cambrian rocks were brought into order, and to some extent zoned. 

 Two distinct types of Lower Cambrian rocks were individualised in Shropshire 

 and Warwickshire, fossiliferous rocks of this age being thus demonstrated to 

 exist in England, and their chief fossil being reconstructed and described. 

 The Welsh Lower and Middle Cambrian rocks were mapped at Harlech and 

 compared with those of the Midlands, just as these in their turn were found 

 comparable with those of the Highlands of Scotland. Deeper still, the rocks 

 of the Longmynd, the oldest massive sediments yet known in the country, 

 were for the first time mapped in detail, proved to be earlier in date than 

 the Cambrian, and compared as to their higher members with the Torridon 

 Sandstone of Scotland, and, as to their lower members, with the problematical 

 rocks of Charnwood Forest in Leicestershire. The underlying rock of the 

 Uriconian group was also mapped in Shropshire, and the occurrence of 

 related rocks proved under the Cambrian of Worcestershire and Warwickshire. 



It was only fitting that one so steeped in the facts should lay down the 

 law as to the nomenclature of the Older Palaeozoic rocks, and particularly 

 that Middle Group, of which, in Scotland, England, Wales, and Ireland, he 

 had become facile princeps. The work of the " old masters " had left this 

 middle group in dire confusion. Lapworth cut the knot, and, impressed by 

 the existence of three great and sub-equal faunas in the Older Palaeozoic 

 rocks, he erected his " Ordovician System " to rank with the Cambrian 



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