TERTIARY FORMATIONS OF OLTENIA 699 



In the Cerna, under the bottom of the river, the complex of marls 

 and sandstones, many banks of alternating sandstone and marls may 

 be seen which contain beautiful leaves of trees and Helicidae and 

 Planorbis. I may add that these strata are very probably the con- 

 tinuation of the sandstone and oolitic limestone with rich mentioned 

 fauna of the Sitoia anticline. These banks would correspond either 

 to the Valenciennesia strata, or, according to Andrussow and Teis- 

 seyre, 1 to a formation which in other localities lies on, or is in con- 

 tinuity with, the Upper Mceotic assise. These Helicidae, and those 

 from Coada Magurei, would indicate a former dry land in this region. 



The corresponding strata at Slatioara and Cucesti were bent into 

 an anticline above the Slatiora island (Figs. 3, 5, 6); a part of the 

 Pontic strata were thrust over the folds of the salt formation. The 

 anticline produced toward the southwest can be made out in the 

 Oltetu valley at Nicoresti-Cursoru, etc. 



1. Andesitic tuff of Gantulesti. — Of great importance for the Pontic 

 petrography of Roumania is the occurrence of a lenticular bank of 

 andesitic tuff at Gantulesti, between Madulari and Armasesti. The 

 rock is porous, fine-grained, with sedimentary Schlieren, and with 

 pseudo-Kaolinitic patches like the pseudomorphs of an unknown 

 vanished mineral. Prismatic crystals of basaltic hornblende are 

 scattered throughout the whole mass of the rock, while the glittering 

 crystals of bytownite occur only in the white patches. The ground- 

 mass is constituted by microscopical glass lapilli, and small crystals 

 of hornblende, bytownite, augite, olivine, etc., show shining crystal 

 faces (no, 100, 101, in, etc.), and form twins; and while the crystals 

 of both are much cracked, we can still separate perfect ones up to 

 2 mm - m length. 



By mixture with sedimentary elements, the tuff receives a water 

 sediment facies, and becomes sandy or marly. 



The bank of tuff, about i m broad, runs eastward from the high- 

 road some ioo m before it terminates; westward it crosses the river 

 Cernazioara, and then is lost to sight because of the wood. Imme- 

 diately above it we find marls and sands with Neritinae, large Hydro- 

 biae, Vivipara Wocdwardi, Unionidae, Cardidae, etc., which corre- 



1 W. Teisseyre, "Die Helixschichten aus Buzau Distr.," Verhandlungen d. k. k. 

 geol. Reichsantalt, 1899. 



