328 bulletin: museum of comparative zoology. 



18. Rhipidomella hybricla (Sowerby). 



19. Plectambonites transversalis (Dalman). 



20. Spirifer crispus. 



21. Schuchertella pecten. 



22. Strophomena euglypha. 



23. \Yilsonia wilsoni. 



24. Omphalotrochus funatus. 



25. sculptis. 



26. Cornulites vagans Schrenck. 



27. Tentaculites ornatus Sowerby. 



28. Orthoceras annulatum Sowerby. 



29. canaliculatum. 



30. Bevrichia klodeni. 



31. Acidaspis marklini Angelin. 



32. Bumastus barriensis. 



33. Calymene tuberculata. 



34. Cyphaspis elegantula Angelin. 



35. Encrinurus punctatus. 



36. Proetus concinnus osiliensis. 



37. Aulacodus obliquus Eichwald. 



Numerous crinoid stems and at least four additional species of 

 Bryozoa are also present. 



Strata of this same horizon are said to make their appearance on 

 the small island of Keinast between Oesel and Moon, and Schmidt 

 reports PalaeocycJus porpita (Linne) and Caryocrinns ornatus Hall to 

 have been collected there. It is extremely probable, however, that 

 the latter identification is incorrect. Farther westward on Oesel at 

 Surika Pank and Hundwa Pank, the lithology of the formation be- 

 comes less dolomitic. As a consequence, fossils are better preserved 

 and, among others, Schmidt notes the occurrence of Thccia sivinder- 

 nana Goldfuss, EridophyUum rugosum IMilne Edwards and Haime, 

 Camarotoechia borealw (Schlotheim), Rhynchotreta cmieata (Dalman), 

 and Leperditia baltica Hisinger. 



Oesel formation. This represents the Upper Oesel group of Schmidt 

 and with it the Silurian of Esthonia ends. The surface exposures of 

 the formation appear to be confined to the southwestern side of Oesel, 

 but there is a possibility that it finds representation among the higher 

 rocks of Moon. It appears to be a direct continuation of the St. 

 Johannis formation and, since there is no appreciable variation of dip, 

 the stratigraphic relations are considered conformable. Probably 



