Reviews—A. Blytt—Displacement of Beach-lines. ie 
logical characters, corresponding to as many paleontological zones. 
Some of the beds are largely crinoidal; the fauna on the whole is 
very varied, and the number of species described is about 200, of 
which 57 are considered as new. Amongst the corals simple forms 
of Cyathophyllum, Zauphrentis and Amplexus predominate. A new 
genus, Briantia, is proposed for simple corals allied to Cyathophyl- 
lum, but with a solid external zone of considerable width. New 
species of Striatopora, Ccnites, and <Acervularia are likewise 
described ; Heliolites, Favosites, Beaumontia, and Alveolites are also 
represented, but no forms of Stromatopora have been recognized. 
The Brachiopoda are very numerous; the principal genera are 
Fhynchonella, with two new species; Orthis, Meristella, Athyris, 
Spirifer, and Centronella? each with three new species; examples 
of Strophomena, Atrypa and Pentamerus are also present. Of the 
Lamellibranchs, the genus Conocardium is the most numerously 
represented. The Gasteropods all belong to the Holostoma, the 
principal forms are included in the genera Pleurotomaria, Murchi- 
sonia, Bellerophon, Strophostylus, and especially Platyceras, of which 
there are no fewer than 12 new species. The Cephalopods are 
mostly included in the subgenus Jovellania, and the Trilobites 
belong to Calymene, Phacops, Dalmanites, Proetus, Harpes, Cheirurus 
and Bronteus. 
The fauna of the Erbray limestones bears a great resemblance to 
the Hercynian fauna of the Harz, and to that of the Etages F. G. H. 
of Barrande. It is referred by the author to the Etage Gedinnian, 
which is at the base of the Devonian in the West of Europe, and it 
likewise corresponds to the Oriskany sandstone and the Upper 
Helderberg of North America and the limestones of the Carinthian 
Alps and of the Urals. It is a distinctly lower stage than that of 
the Coblenzian, which by many authors is still regarded as the base 
of the Devonian. G. J. H. 
a5) da We I a Wate 
J.—Tue PropastEe Cause or THE DIsPLACEMENT OF BEAOH-LINES. 
An ATTEMPT to Compute GxoxtocicaL Hpocus. By A. Buyrr. 
[ Printed in English, Christiania Videnskabs-Selskabs Forhandlinger, 
1889, No. 1. With two Supplementary Notes. ] 
N first thoughts it seems impossible to divine any connection 
between layers of septaria or bands of ironstone, and the 
eccentricity of the earth’s orbit. Yet those who have read with 
attention a previous communication by the same author, “On 
Variations of Climate in the Course of Time,”* will perhaps not be 
surprised at the latest evolution of his doctrines. 
A study of the Recent and Post-Pliocene deposits of Norway and 
Denmark furnished the author with evidence “that climate is subject 
to periodical alterations.” He was also led to conclude that alter- 
1 Reprinted in ‘‘ Nature,’’ July 8th and 13th, 1886. 
