Iviii PROCEEDIX&S OF THE GEOLOt>ICAL SOCIETY. VjL Ixxvii, 



wide-reaeliing correlation, is due to the fact that all but the earliest 

 forms were epiplanktonic, living attached to floating sargasso-like 

 weeds ; and thus, transported by currents, thcA' could reach the 

 most remote areas of ocean and become embedded in the carbon- 

 aceous mud resulting fi'oui the addition of seaweed material to the 

 sediment there forming. 



For the ])urj)oses of his work Lapwoith appeal's to have been 

 satisfied with the then current terminoloo'v of the Arenio:, 

 Llaiideilo. and Bala Series, but he found it necessaiy to link 

 together the Lower and Upper Llandoverv with the Tai-annon 

 rocks as a single series, which he called ' Valentian." But his 

 most important contribution to nomenclature was the inti-oduction 

 of the term " Ordovician," which he proposed, in a closely-reasoned 

 paper, to comprehend the rocks from the top of the Tremadoc 

 to the base of the Valentian. exclusive, on the o^round that they 

 enclose one of the three subequal faunas of the Lower Palaeozoic 

 Era. He subsequently advocated the use of ihis term at the 

 International Geological Congress, and it has now been widely 

 accepted. 



In 1881 Lapworth was appointed to till the newly-established. 

 Chair of Mineraloo-v & Geolos^ at the Mason Colle2:e. Bu'miug- 

 ham. his title being subsequently changed at his own request 

 to that of Professor of Physiography & Geology. He at once 

 began work on the Midland rocks, but found tim.e for two visits 

 to the Highlands of Scotland, which had long attracted him, on 

 account of the manifest obstacles which investigators had 

 encountered there. He foresaw that these difficulties had their 

 roots in complicated tectonics, and he rightly argued that his 

 training in the vast disturbances of the Southern L'plands would 

 be of service in their solution. 



In this supposition he was quite correct. The succession from^ 

 the fundamental ufneiss throuo;h ' Cambrian " and ' Lower Silm'ian ' 

 to the ' Eastern Schists " was not a simple stratigraphical sequence 

 as had been supposed, but was complicated by inversions, faults, 

 and thrust-planes : the rocks were doubled back upon themselves ; 

 and the ' Eastern Schists ' M'ere, in his view, a complex group 

 consisting partly of sediments, but mainly of the fundamental 

 gneiss thrust over younger rocks during older Palaeozoic time. In 

 his paper entitled ■ The Secret of the Highlands, Part I ' he gave 

 the evidence on which he relied for the proof of this contention. 

 He proceeded to parallel his structures with those described by 



