142 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 25, 



The previous arrangements are not without their importance ; for 

 in consequence of the general absence of fossils among the Cumbrian 

 slates and porphyries, one might have started the hypothesis, that 

 these slates and porphyries were but an exaggerated development of 

 the upper Cambrian groups, and that the Skiddaw slate was only an 

 expansion of the dark slates at the bottom of the Bala group. Such, 

 indeed, was an hypothesis suggested to me, in conversation, by M. 

 Barrande ; but it is clearly untenable. 



The descending sections of Cumberland, commencing with the 

 Coniston limestone, are far more vast than the sections of Wales 

 below the Bala limestone ; although we include therein the m.ost 

 deeply seated stratified rocks within the limits of the Principality. 



§ 2. Sections of May Hill, Horderley, and Woolhope, S;c. 



During the past summer I had the great advantage of visiting a 

 part of the typical Silurian country under the guidance of my friend 

 the Rev. T. Lewis ; and, at the time, I had not the remotest hope of 

 adding, during a very short visit, any scrap of information worth re- 

 cording after the ample details published by Sir R. I. Murchison and 

 Professor Phillips. My only hope was that I might add a few good 

 fossils, new or old, to the Cambridge Museum. I may, however, be 

 permitted to remark, in passing, that the colour for the Caradoc 

 sandstone ought in some places to be a little more extended than it 

 was upon the original map of the * Silurian System,' for immediately 

 overlying the Caradoc sandstone of the Horderley section is a shale, 

 with abundant specimens of Ampyx and Trinucleus, which runs down 

 to the bridge over the Onny a little below Cheney Longville. This, 

 perhaps local, deposit might, I think, be conveniently called Caradoc 

 shale ; and my occasional use of this term, during past years, has, I 

 suspect, led Professor M'Coy into the slight verbal mistake to which 

 I before alluded. 



A-gain, it seemed, from the copious details published by Professor 

 Phillips, that there were some other doubtful lines of demarcation 

 even among the most typical Silurian groups. To detremine any of 

 these minute and critical questions would have required a detailed 

 examination, for which I had no leisure ; but I did collect, with the 

 help of Mr. Lewis, a small but good series of fossils from the highest 

 beds of the May Hill section, which rise immediately from beneath 

 the undoubted Wenlock group. This series, determined by Professor 

 M*Coy, was as follows : — 



(1.) Haly sites catenulatus (Dudley). 



(2.) Encrinurus punctatus (Dudley). 



(3.) Pentamerus microcamerus. 



(4.) Leptagonia depressa (Dudley). 



(5.) Leptcena transversalis (Dudley). 



(6.) Orthis turgida (J) . 



(7 .) Spirigerina reticularis (Bala to Devonian) . 



(8.) Strophomena pecten (Dudley). 



(9.) Hemithyris navicula (Ludlow). 

 (10.) Huomphalus funatus (Dudley). 



