284 report — 1865. 



find out the true position and locality of this fossil. Associated with this 

 second species of Paradoxides are three or four other trilohites, two or three 

 shells, &c. 



From this point the beds become still darker in colour, black, flag-like, 

 and slaty beds, full of fossils. A small cavern marks a good line for these 

 highly fossiliferous beds, and here we meet with numerous new species, and 

 even genera, which are not found elsewhere. The beds between the cavern 

 and the traps are the chief repository of our species ; and I will mention 

 more particularly as occurring there two or three new species of Sponge, a 

 Cystidean or two of undescribed form, several minute Braehiopoda, which 

 range through a considerable space, and a host of trilobites, of which the 

 more conspicuous genera are Agnostus, Microdiscus, Conocoryplie of four or 

 five species,'a new genus tEvinnys, allied to Harpides, a new genus Holo- 

 cephalina, and last of all, the great Parad. Davidis, already well known to 

 British geologists. It sometimes attains the length of 18 inches. 



The genus Theea here, as elsewhere, accompanies the primordial fossils ; it 

 is in considerable abundance, and of two or more species. 



Prom a Table which contains the distribution of the fossils in these beds, 

 and which has been carefully drawn up according to observations made by 

 Mr. Salter and myself during the last three years, we are enabled to observe 

 how that many of these species were very short-lived, whilst others on the 

 contrary ranged through considerable spaces, more particularly the smaller 

 species, such as Agnostus, Microdiscus, Lingulella, Obolella, &c. This Table 

 also shows altogether 6 or 7 new geneva of trilobites and about 16 species, 

 and with brachiopod and pteropod shells, Cystideae and Sponges, an addition 

 ■within the last three years to British palaeontology of about 33 new species. 



Notes on the Sections and Fossils. By J. W. Saltek, A.L.S.,F.G.S. 

 I find but little to say regarding the fossils, my friend and colleague having 

 forestalled me, and completed in a masterly way the section I roughly 

 sketched out in 1862. The district around St. David's will soon become 

 popular, as it exhibits the most accessible section of the Cambrian rocks, 

 Lower and Upper, to be seen anywhere in "Wales. Those in the estuary of 

 the Ffestiniog valley are perhaps more complete, but are not seen, except 

 partially, in coast sections ; and nowhere in one continuous series. More- 

 over, lying at lower angles of dip, they are extended over a much greater 

 space. 



Of the following list of 33 species— an ample fauna for the purpose — 

 I may say at once, there are none common to other horizons of the palaeozoic 

 group, and as the thickness of the series is considerable, 3000 or 4000 feet, 

 we only follow the precedent of older and better geologists by proposing a 

 new name. The classic name of the district is Menevia, and we propose 

 that the term ' Menevian' should stand for the Lower, as the ' Ffestiniog' of 

 Prof. Sedgwick already stands for the middle and upper groups of the Lin- 

 gula-flags. The 'Menevian' group, therefore, rests immediately on the 

 'Harlech' or Bangor group of Prof. Sedgwick, and passes imperceptibly 

 into it. 



The Cambrian groups will then stand as follows : — 



( Tremadoc group (Upper and Lower). 

 Upper Cambrian (Lingula-flags) < Ffestiniog group (Lingula-flags). 



( Menevian group (Lower Lingula-flags). 



( Harlech group (Grey grits and purple beds). 

 Lower Cambrian •! Longmynd group (sandstones and conglome- 



( rates). 



