Reviews —Fr. Schmidt's Silurian Leperditie, ete. 420 
IRIE Willa VA Se 
J.—-SupPLEMENT TO THE MonoGRAPH OF THE SILURIAN LEPERDITIZ 
oF Russta; AND A MonoGrarPu OF THE CRUSTACEAN FAUNA OF THE 
EURYPTERUS-BEDS OF ROorzIKiULL IN THE ISLAND OF OESEL IN 
tHe Baurrc. By Fr. Scumrpt. In the Memoirs of the Imperial 
Academy of Sciences at St. Petersburg, 7th series, vol. xxxi. 4to. 
1883. 
VHIS Supplement and the accompanying Monograph constitute 
the “Miscellanea Silurica,’ Part III., published by the St. 
Petersburg Academy, and are valuable additions to paleeocarcinology. 
The author is working also on the Trilobites of the Baltic Provinces 
(for the first part of this work, see Mem. Acad. 7 ser. vol. xxx. 1882); 
but in the meanwhile produces the present papers:—1. To explain 
and illustrate his views of the alliances of the Russian and English 
Leperditig, which have been treated of by himself and Mr. T. R. 
Jones; see the Memoirs of the Academy, ser. vii. vol. xxi. 1873, 
for the Russian Silurian Leperditie; and the Annals Nat. Hist., 
November, 1881, and March, 1882, for notes on the British 
and other species; 2. to compare and illustrate his views of the 
structure and relationship of the Hemiaspide and Eurypteride, of 
which the Island of Oesel yields many specimens from the laminated, 
dolomitic, Upper-Silurian Limestones of the west coast, particularly 
in the parish of Kielkond, below Rootzikill. Here the chitinous 
shells of Hurypterus and Pterygotus are beautifully preserved ; 
the tail-spines of a Ceratiocaris, the cephalaspid shields of Thyestes 
verrucosus, Hichw., and Tremaspis Schrenckii, Schmidt, and the 
shells of the little Lingula nana, Eichwald. Other fossils occur 
as casts only, as Bunodes lunula, Hichw., B. rugosus, Nieszk., B. 
Schrenckii (Nieszk.), Pseudoniscus aculeatus, Nieszk., and Orthoceras 
tenue, Hichw. About 7 versts further to the west, in a ravine near 
the Gesind Wessiko Maddis, a limestone contains a few Hurypterid 
remains, and is covered by shales full of Platyschisma helicites, Sow., 
Leperditia phaseolus, His., and many minute fish-scales, especially 
Ceelolepis Schmidti, Pander. Elsewhere M. Schmidt has found crus- 
tacean fragments in the coral-limestone of his stage K, at Attel to 
the west, and eastwardly at Magnushof, Uddafer, and Ladjal. He 
particularly points out that the Eurypterids are not found here in 
the uppermost Silurian beds, but below others bearing corals, brachio- 
pods, and fish-remains, as M. Schmidt found reason to believe to be 
the case also in Gothland, and in Podolia; in these localities, how- 
ever, Hurypterus Fischeri, Wichw., is the only known species. 
In his new notes on the Russian Zeperditie M. Schmidt offers a 
revision of the species met with in the Baltic Provinces, with a 
sketch of their distinctive characters, and of their vertical range. 
He uses A to K for his new stratal divisions of the Hast-Baltic 
Silurian formation, as givep in Prof. Grewingk’s new geological 
map of Estiand, Livland, and Kurland, and in the introduction 
