1863.] WRIGHT ECHIimLE OF MALTA. 277 



for his zeal and kindness, I name the species*) to work at the lower 

 black slates in the neighbourhood of Ffestiniog, not far above their 

 junction with the Cambrian beds, where they will surely meet with 

 these species. 



The following succession of beds, in ascending order, in the Pri- 

 mordial zone, has now been established in "Wales, and it is the same 

 in South as in North Wales : — 



Red and purple grits becoming intermixed with | Cambrian (G e l og ical 

 some greenish-grey sandstones where they pass up V ^ >. v ° 



Lingulella, rare. 

 Olenus, common. 

 Agnostics, common. 

 Paradoxides Davidis. 



into 



1. Lower Lingida-flags. — A thick mass of black 

 shales, very uniform in its upper part, but with 

 much sandstone in the lower ; probably accumulated 

 in deep water. 



2. Middle Ling id a -flags. — A thick series of hard 

 light-coloured sandstones, with ripple-markings, 

 worm-tracks and burrows, and other evidences of 

 having been accumulated in shallow water 



Lingidella Da visit, abun- 

 dant. 

 Olenus, rare. 

 Hymenocaris, abundant. 



/ Olenus, many species. 

 3. Upper Lingula-flags. — A thin series (not more | Agnostus, abundant, 

 than 300 feet at most) of fine black shales, crowded \ Conocephahcs. 

 with small Crustaceans ; shells very rare ; deep water. | DiJcellocepkalus. 



^ Orthis, small species. 



The best general section in the neighbourhood of St. David's is at 

 Whitesand Bay, where the Cambrian Rocks and Lingula-flags are 

 seen to be overlain by a lower member of the Llandeilo formation, 

 of which and its corresponding beds elsewhere there is not space here 

 to treat properly ; I hope to do so shortly. 



The constant occurrence of the same large forms of Trilobite 

 (generally, too, accompanied by the minute Agnostus) in the lowest 

 strata in which anything like a fauna is known, of different species 

 in each district, and yet distributed so widely in Europe and America, 

 is surely a curious fact, in any view of the origin or distribution of 

 species. Both these genera depart widely from the general type of 

 the Trilobites. 



3. On the Fossil Echinid.e of Malta. By Thomas Wright, M.D., 

 F.R.S.E., F.G.S. With Notes on the Miocexe Beds of the Island ; 

 by A. Leith Adams, A.M., M.B., Surgeon of H.M. 22nd Regiment. 



[The publication of tins Paper is postponed.] 



(Abstract.) 



The Echinoderms described in this paper by Dr. Wright were dis- 

 covered by Dr. Leith Adams during a careful examination of the 

 strata and geological features of Malta. A description of the Mio- 

 cene beds was given by the latter gentleman, in which he stated his 



* David Homfray, Esq., of Port Madoc, Caernarvonshire, who. together with 

 Mr. F. Ash of the same place, has for many years successfully explored the Pri- 

 mordial zone and the overlying beds. 



VOL. XIX. PART I. r 



