British Association — Section C. 519 



whicli had then been examined were also stated to be most probably 

 of Lower Arenig age.^ 



Since then a new series of graptolite beds have been discovered 

 on Ramsey Island, and the author had examined the graptolites 

 collected. Owing to their fragmentary condition the following 

 species only could be determined: — ■ Didijmograptus affinis, Nich. ; 

 D. hifidus, Hall; D. geminus. His. sp. ; D. patulus, Hall ( = D. hirnndo, 

 Salt.) ; Diplograptus dentatus, Brong. sp. [=D. pristiniformis, Hall) ; 

 D. miicronatus, Hall ; and Climacograptus scalaris, Linn. sp. 



The evidence ajBbrded by these species was considered to be 

 decidedly in favour of the view that these new Eamsey Island beds 

 are of Upper Arenig age, and therefore higher than those previously 

 known. 



Comparing the, graptolites of the Skiddaw slates of Cumberland 

 and the Arenig rocks of Shelve with those of the Lower and Upper 

 Arenig rocks of Eamsey Island, there appeared, upon the whole, to 

 1)8 a parallel succession of species in the Shelve and St. David's 

 rocks, the Dendroidea abounding in the lower beds in each area, and 

 the slightly diverging species of Didymograptus, with species of 

 Diplograptus and Climacograptus, being found in the upper beds 

 only ; while the Skiddaw series, in which no dendroid graptolites 

 are known to occur, seemed to be more nearly related to the upper 

 than to the lower Eamsey Island beds ; and it was. inferred that the 

 Skiddaw slates, which have hitherto been considered our oldest 

 graptolite-bearing rocks, are of more recent age than the lowest 

 graptoliferous rocks of St. David's, 



III. — " On the Occukrence op Numerous Species of G-raptolites 

 IN THE Ludlow Eooks of Shropshire. By John Hopkinson, 

 F.G.S., F.R.M.S. 



Until recently only two species of Graptolites, Monograptus 

 (Graptolithus) priodon and M. colonus, were believed to occur in the 

 Ludlow rocks of Shropshire. In 1868 Dr. Nicholson added to these 

 a new species of Ptilograptus, and mentioned the presence of an 

 additional species of Monograptus. These had been collected by 

 Mr. Lightbody of Ludlow, who had also found a few other species 

 in these rocks. 



In the course of an excursion of the Geologists' Association to the 

 Silurian rocks of Shropshire, in July, 1872, and during a subsequent 

 visit which the author had recently paid to Ludlow and its neigh- 

 bourhood, several other species had been found, and some information 

 on the distribution of the species had been elicited. 



While, however, the number of species known to occur in the 

 Ludlow rocks have been greatly augmented by these researches, one 

 or two forms hitherto supposed to be characteristic of one or other 

 division of these rocks had not been found in them. Not a single 

 specimen of Monograptus priodon had been seen in the Ludlow rocks, 

 all that had been found being from the Wenlock shale ; and not a 



1 See Geol. Mag., Vol. IX., p. 467, and Trans. Liverpool Geol. Soc, sessioa 

 1872-3. 



