RAYMOND: CORRELATION' OF THE ORDOVICIAX STRATA. 195 



ate showing that it was formed at or near the shore, and at a time 

 immediately subsequent to a period of erosion. 



The Kunda formation has a somewhat irregular thickness, being 

 thickest in the east and very thin at the west. On the ^Yalchow it is 

 thirty-two feet according to Lamansky, at Papowka it is thirty-four 

 feet with the top not seen, at Ontika eighteen and one half feet, at 

 Asserien fourteen and two thirds feet, at Kunda fifteen feet, at Reval 

 four feet, and three and one half feet at Packerort. The abundant 

 fauna at Reval is practically the same as that at Kunda, but as the 

 fauna seemed to be the same all through the section at Kunda, this in 

 itself would not indicate whether the thinness at Reval was due to 

 erosion at the top of the formation or to a smaller original deposition, 



Schmidt states that west of Reval the Orthoceras limestone passes 

 into a sandstone, but I myself saw no evidence of this, either at Baltish- 

 port or on the Island Rogo. At these localities the formation consists 

 of a rather thick-bedded hard limestone without many fossils, and at 

 the base is a conglomerate made up of pebbles of green glauconitic 

 limestone and irregular pieces of dark shale, these latter proving on 

 analysis by Kupffer to contain, in some cases, a large percentage of 

 phosphoric acid. 



The fauna of the Kunda formation is dominated bv Mollusca, 

 mostly cephalopods and gastropods. Pelecypods are rare, making 

 here their first appearance in the Russian section. Typical fossils 

 are Vaginoceras vaginatum, V. commune, Maclurites helix, Estonio- 

 ceras lamcUosum, Asaphus raniceps, Pliomera fischeri, Lycophoria 

 nucella, and Ptcrygomctopiis sclerops. 



^YIERLAND GROUP. Cl, 2 and 3, and part of Di (Echinosphaerites 

 limestone, Kuckers schicht, Itfer schicht, and basal portion of the 

 Jewe schicht), of Schmidt. 



As already noted, Schmidt gave geographic names to all the strata 

 above the " Glint," but these names are of very unequal value, some 

 of them designating true formations, and others indicating merely 

 the quarry at which a certain fauna or type of strata was seen. The 

 faunas of all three of the formations named above are vevy closely knit 

 together by the presence of Echinosphaerites aurantium and species of 

 Chasmops. The name Wierland which I have applied to the group 

 is that of the district in which most of the localities for Kuckers and 

 Itfer are located, and in which the lower divisions are well developed. 

 The lower members are also given geographic names to correspond to 

 the two upper members named by Schmidt. There is really a greater 

 faunal change between the Reva;l and Dubowiki members than be- 

 tween any other two in the group. 



