TRANSACTIONS-% THE SECTIONS. 69 



Such are the data which studies carried on during more than fifteen yearg enable 

 me to bring forward. Their application to engineerin;^ does not come within my 

 province ; I lea^-e that entirely to the eminent man who is carrying out this great 

 work, and who I hope will master all obstacles. 



On ilie Oeohgy of Neiv Zealand. By Dr. J. Hector, F.R.S. 



On some Areas ivliere the Cambrian and Silurian TtocJcs occur as Conformable 

 Series. By Henky Hicks, F.O.S. 



The author stated that of late years it has been generally supposed that there 

 was strong evidence in many Welsh sections of the presence of several important 

 breaks in the succession in these rocks, and that the series forming these formations 

 were not deposited over an area becoming gradually depressed, the usual idea being 

 that the area was at one time under water and at another dry land. That this 

 was really the case over limited areas he was not at present prepared to deny ; but 

 he thought the evidence of this was as yet imperfect. In other cases, however, he 

 was prepared to contest this view, and, amongst other sections, mentioned the 

 following as showing conclusively that there was not the slightest evidence of the 

 presence of an unconformity. 



In Pembrokeshire the succession from the Cambrian to the top of the Llandovery 

 rocks is a perfectly continuous one ; and there are no breaks seen anywhere but such 

 as are produced by faults. 



In the neighbourhood of Llandovery, the Oaradoc, Lower Llandovery, Upper 

 Llandovery, Wenlock, and Ludlow beds are seen resting quite conformably upon 

 each other. 



In parts of Sliropshire, the Caradoc, Lower Llandovery, Upper Llandovery, 

 Wenlock, and Ludlow are also seen, and there they also appear to be conformable ; 

 in the neighbourhood of Cornwen, in Merionethshire, the sections also appear to show 

 a regular succession from the Caradoc through the Tarannon shales to the Derbyshire 

 slates, flags, and grits. 



He therefore looked upon these areas as portions of one gi-eat and gi-adually 

 subsiding area, which remained continually under water, and received deposits 

 Tininterruptedly from the commencement of the Cambrian to the close of the 

 Silurian epochs. Pie believed that this was the case over the whole European area 

 where not greatly disturbed by volcanic forces. 



On tlie Distribution of the Graptolites in the Lower Ludlow Roclcs near Ludlow. 

 By John Hopkinson, F.L.S., F.G.S. 



The author first drew attention to the special interest attaching to the Ludlow 

 rocks, in connexion with investigations on the vertical distribution of the Grapto- 

 lites, as being the formation in which they apparently die out. 



The Rhabdophora, or true Graptolites, which, with the Cladophora, or dendroid 

 forms, we find in infinite variety when they first appear in the Ai-enig rocks, genera 

 the most complex coming in simultaneously with simpler forms, were stated to be 

 represented in the Lower Ludlow rocks by but a single genus, and that the simplest, 

 Monograptus — and the Cladophora also by one genus only, Ptiloyraptus. 



A list of the Graptolites of the Ludlow rocks, given in a former communication 

 to the British Association (1873), was then alluded to*, and the main conclusions as 

 to the distribution in these rocks near Ludlow of the species enumerated, arrived 

 at in the course of a few days spent at Leintwardine immediately before the opening 

 of the present Meeting, were given. 



It was shown that several species of Monograptus abound in the lowest beds of 

 the Lower Ludlow, when these lowest beds do not, as they do near Stokesay, form 

 a limestone divided from the Wenlock Limestone by a few feet of shales ; that some 

 * Eep. Brit. Assoc, for 1873, Trans. Sections, p. 8.^. 



