360 
SILURIA. 
[Chap. XIV. 
grey beds of the Baltic Islands are manifestly the equivalents of the Upper 
Ludlow rock of Shropshire, on account of many of their invertebrated organic 
remains. 
The work by Fr. Schmidt, 1 Die Silurische Formation von Esthland, Nord- 
Livland, und Oesel ' (Dorpat, 1858), completely sustains the views expressed in 
my previous edition. Little justice, however, is done to M. Schmidt's valuable 
details in this volume; and the reader who does not consult the original is 
referred to my memoir in the Quarterly Journal of the Geological Society, vol. 
xiv. p. 43, ' The Silurian Rocks and Fossils of Norway and the Baltic Provinces 
of Russia,' in which M. Schmidt's researches are fully treated of. 
In his examination of Gothland, M. Schmidt has ascertained that the sketch 
which I gave in 1847, respecting the British equivalents of that exclusively 
Upper Silurian Island, is correct. In proceeding from the Wenlock Shale and 
Limestone on the north, M. de Verneuil and myself reached younger strata on 
the south, the highest of which represented the Upper Ludlow Rock. This 
view, though at first opposed by Helmersen, has been supported by Schmidt, 
who, among other arguments, has shown that the strata at the south end of 
Gothland contain the same species of Eurypterus (E. remipes ?) as the upper- 
most beds of the opposite Russian Isle of Oesel, which contain numerous 
Ludlow-rock fossils. 
M. Schmidt has given a detailed list of all the known Silurian fossils of the 
Russo-Baltic Provinces. Among about 425 species enumerated, the Corals, 
Graptolites, &c. amount to nearly 80 species ; the Crinoidea, Cystideae, &c. to 
13 ; Cornulites, Tentaculites, and other Annelides to 5 ; the Polyzoa to 16 ; 
the Brachiopoda to nearly 100; the Acephala, Pteropoda, Heteropoda, and 
Gasteropoda to 69 ; the Cephalopoda to 39 ; the Crustaceans, including Bey- 
richia &c, to 67; and the Fishes (all of which, as in England, are in the 
Uppermost Silurian zone) amount to 40 species. 
No one has laboured more successfully than my old colleague General Hel- 
mersen in elaborating the true structure of Russia. Since I quitted that country 
he has thrown light on many parts which my associates and self had not time 
to explore, and has published a map containing some important additions to that 
which we produced in the work ' Russia and the Ural Mountains.' He has 
also recently transmitted to me the following information : — 
On the River Dniester, where my associates and self had inserted Silurian 
rocks upon our Map, M. Malemsey, a young student of the University of Kief, 
has discovered in limestone, shale, and sandstone, at Kamenetz, Kitaigorod, and 
other places in Podolia, a great number of fossils, which he has referred respec- 
tively to the formations of Llandeilo, Caradoc, Wenlock, and Ludlow. 
Not attempting to assign to each fossil its exact place in the British Silu- 
rian series, I simply give M. Malemsey's list of the fossils which, as he sup- 
poses, represent the English formations, classing them as Lower and Upper Si- 
lurian specimens, and affixing to each a letter, as L. for Lower Silurian, U. 
for the Upper division, L. U. for those which occur in both deposits, and 
D. for Devonian : — 
Amorphozoa. — Stromatopora polymorpha (u. and d.). 
Coelenterata (Zoophyta). — Acervularia ananas, Linn, (luxurians, Eichw.) (u.) ; Chas- 
tetes Fletcheri, M.-Edwards (u.) ; Coenites intertextus, Eichw. (u.) ; Cyathophyllum 
articulatum, Wahl. (l. u.) ; C. ceratites, Goldf. (d.); C. flexuosum, Linn, (u.) ; C. qua- 
drigeminum, Goldf. (d.) ; C. vermiculare, His. (articulatum, Wahl.) (l. u.) ; Favosites 
Gotlandica, Linn. (l. u.); Fistulipora decipiens, M'Coy (u.); F. cribrosa, M'Coy (u.); 
Halysites catenularius, Linn. (l. u.) ; Heliolites interstinctus, Linn. (l. u.) ; H. Mur- 
