42 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 6, 



Even the upper limestones, schists, and shales, as seen at Malmo 

 and the places above cited, are still charged with some corals and 

 crinoids, known in England only in the Wenlock formation, including 

 among the latter, Eucalyptocrinus decorus and Crotalocrinus (Cya- 

 thocrinus) rugosus. On the other hand, here are also found some 

 of the typical species of the Ludlow rocks, viz. Chonetes (Leptcena) 

 lata, Rhynchonella Wilsoni, R. navicula, Turbo corallii, Pterinea 

 retroflexa, Orthoceras Ibex, &c. 



In my own rapid survey of the environs of Christiania, as formerly 

 explained to this Society, I could not, any more than M. Kjerulf, 

 detect fossils indicative of the uppermost Ludlow rock, though I 

 first pointed out the conformable passage upwards from the grey 

 Silurian rocks into an overlying red sandstone. In some parts 

 of Sweden, however, and on another occasion, my coadjutor M. de 

 Verneuil and myself detected organic remains in strata which must, 

 we thought, represent the Upper Ludlow, and even a transition into 

 the Devonian. Thus, in Scania we found true Upper Ludlow fossils 

 in red flaggy sandstones which Forchhammer had classed as Old Red 

 Sandstone *. 



Again, in proceeding from the northern and central parts of Goth- 

 land, which are occupied by the Wenlock limestone, we at length 

 reached beds of a sandy and marly character, in which some of the 

 species above mentioned, including the Pterinea retroflexa, Chonetes 

 lata, and Turbo corallii, were collocated with the Rhynchonella 

 {Terebratula) nucula, Orthonota retusa, Murchisonia articulata, 

 and Beyrichia tuber culata, all fossils of the Upper Ludlow rock. 

 As these forms are, in the ascending order, associated with fossils 

 which occur in the Eifel and other Devonian tracts, including 

 the Calceola sandalina, it was presumed, that the southern pro- 

 montories of Gothland offer a passage from the Silurian into the 

 Devonian rocks. 



In the meantime we learn by these evidences, how, with the vary- 

 ing conditions of the seas during these epochs, the same species 

 have had a longer existence in one region than in another. 



M. Kjerulf has verified, in situ, all the organic remains he enume- 

 rates, and has followed each band of rock throughout all its undula- 

 tions or breaks in the Bay of Christiania. From his numerous sec- 

 tions I have extracted three, which are annexed (p. 38). The first 

 of these is the general diagram, fig. 1, the second (fig. 2) repre- 

 sents the ascending order near Beston Kilen, from the lowest fossil- 

 iferous beds, No. 2 (alum-slates, or " primordial zone"), through the 

 lowest graptolite-schists (3), the Orthoceratite-limestone (4), and the 

 Upper Graptolite-schists (5), — the three beds representing the Llan- 

 deilo flags, to the calcareous and argillaceous flags, 6 &7, containing 

 Caradoc fossils : all these beds and fossils are Lower Silurian, and 

 are seen to be overlaid by the basement-beds of the Upper Silurian, 

 Nos. 8 & £. 



The third diagram is a section from Ormo, across the whole island 

 of Malmo, and exhibits at the base Nos. 6 & 7 of the Lower Silu- 

 * Quart. Journ. Geol. Soc. vol. iii. p. 34. 



