it DESCRIPTIVE REMARKS. 
The following Table of the number of species of British Silurian 
Fossils found in each formation is compiled from ‘“ Siluria,” fourth edi- 
tion, 1867, pp. 508-5386. 
‘ 3 q S E ad o 
ag 33 3 8 5 8 B og 
= 8 | rg = S & ze) so 
Aa Bes A 5 3 5 = es) 
a ba | 4 é E B a | é 
AY HA 3 
4 
9 | Plant (some doubtful), . al 0 0 0 1 1 6 
17 | Protozoa, Class Amorphozoa, D) 9 Ah Seale 2 4 
139 & 4?) Cwlenterata, Class Actinozoa, . | 0 3 | 24&27) 31 &12 7&1? 11 
55 & 12 9 Graptolitidee, Hydro- 
zoa (Dictyonema is { | } 
included with Poly- { ler a0 40 9 oe ! 0 
z0a), . 
85 & 12} Annulosa, Echinodermata, a 0 0 24) 7&1? 37 17 
46 | Annulata, Annelida, ; =| 4 14 10 4 6 8 
366 & 2?) Articulata,Crustacea, ‘ al) 7 75 103 | 29 & 12 52 61) 9& 
1 Cirripedia, : ol 0 0 0 0 1 0 
45 Mollusca, Molluscoida, H : D 
Class Polyzoa, (ph 5 874 3 15 3 22 0 
309 & 72 Molluscoida, f 5 : 
x Class Brachiopoda, § 13 25 75 | 74 & 32) 88 & 4? 33 
44 &1? of emu ra neniete ) | 0 0 7&12 7 15 15 
si ide 
131, Biplonida, ” : 0 5 | 36& 22) 25&17 6&1? 48 
123 & 1? = Class Gasteropoda, . 0 7 b4 | 34 & 1? 7 30 
35 Heteropoda 8 9 4 5 
2 (Nucleobranchiata), j u q 
34 & 1? i Class Pteropoda, . 3 10 | 9&1? 3 5 3 2} 
107 & 3? Class Cephalopoda, . 0 5&1? 31 20 | 22 &14) 29812 
144&1? Vertebrata, Class Pisces, ; 0 0 0 0 0 8] 6& 
1560 & 26? Total number of species, 1586, including 26, the relations of which are doubtful. 
The list of Primordial Silurian fossils has now been considerably 
augmented by the labours of Mr. H. Hicks, the late Mr. Salter, Mr. 
Thos. Belt, F.G.S., Mr. John Plant, F.G.S., and Mr. E. Williamson, 
F.G.S. In the neighbourhood of St. Davids, in South Wales, and 
near Dolgelly and Maentwrog i in North Wales, immediately beneath the 
Lingula flags, is a series of dark- -grey and black flags, alternating with 
some beds of sandstone, the whole comprising a thickness of from 500 
to 600 feet: these strata were formerly considered to be the base of the 
Lingula flags, solely on lithological grounds. Messrs. Hicks and Salter 
have. however, shown that the fossils, of which more than 40 species 
have been found in them, are distinct from those of the Lingula flags. 
The Trilobites described by those gentlemen included Paradoaides 
Davidis, P|. iv., fig. 3, the largest example known in Britain; they 
propose to place these strata at the top of the Lower Cambrian, under 
the term ‘‘ Menevian,” Menevia being the classical name of St. Davids. 
Norr.—In the Explanation of the Plates, p. 10, Olenus humilis, Pl. iv., fig. 6, is 
stated to be only known in the black shales (Lingula beds) of Malvern; Mr. John 
Plant has since obligingly informed me that he has several hundred specimens which he 
collected in Lower’ Lingula Beds, at Tyddyngwladis, North Wales, with many new 
species. 
cre 
Boo Oo KK oO = So oro 'S: 
> 
