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TWENHOFEL: EXPEDITION TO THE BALTIC PROVINCES. 52] 
On the coast south of Hapsal, near the village Pasko, are extensive 
exposures of a white crystalline limestone. The outcrops are on the 
beach, and the rock appears to have been formed from an old coral 
reef. Well-preserved coral masses strew the beach and have con- 
tributed a great deal of material to the many stone walls of the ad- 
joining lands. These are the most fossiliferous exposures of this 
division that were seen. The corals consist of Favosites, Heliolitidae, 
Halysites, Clathrodictyon, eo aa Acervularia and several 
species of horn corals. 
Other localities where the Raikiill beds are exposed are Mexhoff, 
Piometz, Endama, Allenkiill, Teknal, Wieso, Wédja, Tenja, and the 
island Kassar to the south of Dago. 
Besides the corals mentioned as being present in the Raikiill beds, 
there are the trilobites Encrinurus punctatus, Illaenus livonicus Holm, 
Phacops elegans Sars and Boeck, Proetus planedorsatus; the bryozoans 
Vineularia megastoma Eichwald and V. nodulosa Eichwald. Brachio- 
pods appear to be quite rare. At Raikiill and Wahlokiill Schmidt 
states the occurrence of the graptolite Diplograptus estonus Schmidt ! 
and at the latter place Deiphon forbesi Barrande. 
Addifer formation. This formation was designated by Schmidt 
the Pentamerus estonus beds by reason of the great numbers of that 
brachiopod which are commonly present. The section exposed in the 
quarry at Addifer, the estate of Herr E. von Wahl, is taken as the 
type. 
The outcrops of the Addifer formation begin about twenty miles 
west of Lake Peipus near Pedja Brook and reach the sea south of 
Hapsal. It has not been identified on the islands, but may underlie 
the extreme southern end of Dago, and probably does underlie Soela 
Sound between the islands of Dago and Oesel. The thickness of the 
formation has never been accurately determined, but it appears that 
not more than fifty feet are present. 
The formation is separated from that underlying, chiefly on the 
basis of the introduction of Pentamerus estonus Eichwald, Atrypa 
reticularis (Linné) and LEospirifer radiatus (Sowerby). So far as 
known, its stratigraphic relations to the Raikiill beds and St. Johannis 
formation are those of conformability. 
The designation, Pentamerus estonus beds, does not carry the idea 
that the rocks are largely composed of the shells of one species, as is 
the case in the P. borealis beds. In this formation the pentamerids 
1 Mem. Acad. imp. sci. St. Petersb., ser. 7, 30, no. 1, p. 44. 
