604 



is proved by the sporadic Foraminifera. Higher up the clays are 

 gradually pushed back by coarse-clastic layers, built up of volcanic 

 material, while the most recent layers of the plicated Tertiary 

 consist exclusively of volcanic sands and tuff-breccia, dipping beneath 

 the Gedsch-massive at a slight angle. 



The clay-formations can be traced towards the East up to the 

 spot where Verbeek has roughly indicated the western limit of 

 the "Old Andesites" — i. e. along the upper course of the 

 Tji-Teureup. Between the rivers Tji-Djanjanti, Tji Teureup, and 

 Tji Keas, the bulbous shale, free from volcanic n^aterial, can 

 again be seen wherever the solid rocks emerge. Between the upper- 

 course of Tjikeas and Tji-Teureup, over a zone of little breadth but 

 of 1 km. length (direction about N. 20° W.) many huge "wool- 

 packs" (some of them 100 m') of andesite are lying in or on the 

 clav-formation, forming an immense field of blocks. It cannot be 

 made out, whether tiiese blocks — like the numerous smaller ande- 

 site fragments occurring all over the area (cf. page 601) — are the 

 remains of a discordant young covering of tuff-breccia, or whether 

 they are the line of outcrop of an andesite dyke breaking through 

 the clay -formation. 



In the upper-course of the Tji-Teureup we find the familiar clay- 

 rocks, here including Globigerina and moreover slightly silici- 

 fied, so that it can be ground. It slopes down towards the South- 

 west amidst disclosures of andesite-rocks which, downstream, pass 

 into a granular-crystalline, diorite-like rock. It is interesting to note 

 that tlie hollows of the Globigerina are often silicified. A most 

 peculiar brecciated limestone, including Lepidocyclina and Amphi- 

 stegina, occurs in concordant arrangement with this clayrock. It is 

 made up of irregular limestone fragments, some of them highly 

 crystalline, cleft by thin intermediate layers of the clayrocks just 

 described. It seems as if the limestone has been broken to pieces 

 during the plication of the mountain ground and particles of the 

 plastic clay have been intercalated by pressure. So we see that close 

 to the contact with the old andesites, nay, surrounded by them on 

 nearly all sides, we find a tertiary formation, absolutely devoid of 

 volcanic material. 



The claystones occurring here, differ from the shales, found more 

 to the West, in being more consolidated on account of only a slight 

 silicification. 



When going down the Tji Teureup, encountering all the way 

 normal, imperfectly stratitied shales, we approach the magnificent, 



