Notices of Memoirs — Geology of Nassau. 365 



DisroTioiES OIF nycEnynoiies- 



I. — A Short Sketch of the Geology of Nassau. ' 



THE characteristic geological formations of the Province of Nassau 

 belong to the Devonian series, and are named from the geograph- 

 ical site where they are most clearly developed, the Khine System. 

 The lower strata of this system are of a sandy character, and show in 

 their fossil remains a predominance of Brachiopods (Spirifera, Orthis, 

 Terebratula) , and of these Spirifera macroptera occurs by far the 

 most frequently, on which account Sandberger has classified the upper 

 strata as the Spirifer Sandstone. Of other families of MoUusca, the 

 Pleurotomaria Daleidensis, Bellerophon trilobatnm, and Conularia 

 ( Coleoprion) gracilis are found in great numbers, but within a limited 

 area. In Crinoidea the genus Ctenocrinus is peculiar to the Spirifer 

 Sandstone, and fragments of the arms of these and of the genus 

 Isocrinus are abundant. Crustacea are represented by the genus 

 JTomalonotus. Pleur acanthus laciniatus is the fossil most widely 

 disseminated ; but the Pleurodictyum problematicum must be regarded 

 as the most characteristic in this group. 



Contrary to the opinion of Murchison and Sedgwick (Geol. Trans, 

 vol. ii. page 221), who are inclined to refer these beds to the Silurian 

 system, the German geologists Sandberger and Eomer regard them 

 as a separate formation, approaching the chalky beds of the Ehine 

 system more nearly in the character of their fossil remains. The 

 superposed strata show a still more calcareous character, and have a 

 far greater variety of fossil remains, corals, and gasteropodous mol- 

 lusca. As characteristic species may be cited String ocephalus Bur- 

 tini, various species of Pleurotomaria, Euomphalus, Terebratula, and 

 two Spirifers of a different species from those met with in the strata 

 just mentioned. Among the Crustacea the genus Cypridina is most 

 frequently represented, especially in the upper layers. The general 

 character of the fauna point to an epoch in the formation of the land 

 when the sea had retreated, leaving only inland lakes, on whose 

 borders a new order of animal life could find a suitable habitat. 



Above the sandy and chalky beds of the Ehine system lie a series 

 of rocks, which resemble most closely the Coal-formation, both in 

 their lithological character and their fossil contents. Especially is 

 this the case with the flora. The fauna presents partly the same 

 character as the limestone, and partly shows a new and entirely 

 distinct facies. It is more fully developed in Westphalia, the Harz 

 mountains, and in Devonshire. The fauna is not so manifold as that 

 already noticed; the characteristic fossil from which the rocks are 

 indeed named by German geologists is Posidonomya Beclieri ; Pecten 

 and Goniatites are also found, but mostly in a very fragmentary 

 condition. The remains of plants, on the other hand, are more 

 numerous and better preserved. Calamites Suchoivii, Cyperites bicari- 

 nata, and many other still undetermined species, frequently occur. 

 A fern of the genus Sphenopteris is met with, but more rarely. 



^ Being a brief abstract of Dr. F. Sandbergei's recently published book on the 

 Mineralogy and Geology of ifassau. 



