lO JOHAN Kl.l-.R. M.-X. Kl. 



liavc fallen from the porjjliyry wall. The lower jjart of Ibis huge series 

 consists of red-brown, micaceous calcareous sandstone, generally in thick 

 beds. Crossbedding is common. These beds can also be split into slabs 

 and used for flagstones and many other purposes. Slabs have been 

 quarried here from olden times onwards, and a number of small quarries 

 still exist, altliough they arc now for the most part abandoned. Small 

 flakes of shale are quite common in the sandstone, but thin layers of 

 shale are rare. In the upper beds, brown-red sandstone alternates with 

 a slightly red, gray-green or greenish sandstone in beds of greater or 

 smaller thickness. In the uppermost part the gray-green colour appears 

 to predominate. The sandstone here too is micaceous and calcareous, 

 about the same as farther down in the series. 



The thickness of the sandstone series in Ringerike is here consider- 

 ably greater than given by KjERULF. According to the sections, the 

 lower part in the neighbourhood of Sundvolden, is at least 200 m. I 

 have estimated the upper part at about 300 m. at least. The total 

 thickness is then probably at least 500 m. I am however of the opinion 

 that these estimates will prove much too low. 



The Fossiliferous Section at Rudstangen. 



The lowest schistose beds of the sandstone series are exposed 

 only in two sections at Kroksund. One is the section pre\iously 

 known 1 at the main road between Kroksund and Vik, in which 

 section the direct transition from the uppermost fossiliferous zone of 

 Ludlow (9 g) to the red schists and calcareous sandstones can be studied 

 with great ease. The second is situated farther in the south-west at 

 Rudstangen, and as regards the Ludlow beds, has been briefly mentioned 

 in my paper on the Upper Silurian -. 



In the first section real fossils have not hitherto been discovered. 

 Th. Münster however, found here two different trails, one of which 

 corresponds to those which occur quite commonly at Rudstangen. 



I have myself discovered other curious impressions the origin of 

 which cannot as yet be explained. 



On the other hand, the section at Rudstangen is the only one 

 where remains of animal life of our sandstone have so far been found. 



Rudstangen is a beautiful richly wooded tongue of land, along 

 the south coast of which the strata are well exposed. Furthest to the 



1 J. K i aer: Das Obersiliir im Kristianiagebiete 1908, Pag. 115. 

 ■' Ibidem, Pasre 116. 



