84 Revieivs — Prof. Dames — Strata of Heligoland. 



To tlie above modification of the Concrescence Theory of 

 Kiikenthal and Kose cannot be applied the reproach that " it comes 

 from a one-sided Morphology which regards only the wonderful, 

 though mutilated, chapters of Embryology when the untom pages 

 of Palaeontology are at hand." ^ 



11. — ITeber die Gliederung der Flotzformationen Helgolands. 

 Von W. Dames. Sitzungsber. der k. preuss. Akad. d. Wiss. zii 

 Berlin, 1893. pp. 1019-1039. 



On the Divisions of the Stratified Formations of Heli- 

 goland. By Prof. Dr. W. Dames. 



IT is quite natural that the little rocky islet of Heligoland, lately 

 transferred from the British to the German Empire, should 

 have been examined by its new possessors with that warm interest 

 which generally accompanies recently acquired ownership, whether 

 by persons or by nationalities. From a geological point of view the 

 rocks of this islet had been considered to show a pronounced re- 

 lationship to those of the English coast on the other side of the 

 North Sea, but Prof. Dames, who has spent several weeks this last 

 Autumn in studying its geology, maintains in the present paper, and 

 we think successfully, that they bear the closest resemblance to 

 those of Schleswig Holstein and other areas in North Germany, and 

 consequently that Heligoland is but an advanced post of German 

 territory, with which, geologically, it has had an almost unbroken 

 connection since the close of the Palseozoic period. 



Hitherto the rocks of Heligoland have been referred to the 

 Triassic, Jurassic and Cretaceous formations, but Professor Dames 

 states that Jurassic strata are absent altogether. The lowest beds on 

 the main island consist of reddish-brown, thick-bedded calcareous 

 clays, with traces of copper ores, which are closely similar, petro- 

 logically, to the strata of Zechstein age in Schleswig Holstein, and 

 to those on the same horizon on the flanks of the Harz Mountains. 

 Conformably overlying the Zechstein on the main island are red and 

 green speckled clays, sandstones and dolomites, considered of Lower 

 Bunter age — in these a characteristic rib of a Triassic saurian has 

 been found. The Middle and UiDper Bunter beds probably come 

 in beneath the North Sea, between the main island and the Wite 

 Klif. This latter is of a yellowish clayey limestone or dolomite, 

 containing mollusca characteristic of the Lower Muschelkalk. The 

 Middle and Upper divisions are represented by beds of gypsum 

 and glauconitic limestones and dolomites. 



The rocks succeeding the Upper Muschelkalk dolomites contain 

 fossils of Lower Cretaceous age similar to those of the Speeton Clay 

 of Yorkshire and of Simbirsk, in Eussia, and the following zones 

 have been recognized by the author in the so-called Tock beds : 



1. Zone of Belemnites pistilliformts, with Exogyra Couloni and 

 Pecten crassitesta, belonging to the Neocomian. 



2. Zone of Belemnites bnmsvicensis, with large undescribed species 

 of Crioceras. 



1 See American Journal of Science, December, 1893, p. 448. 



