twenhofel: expedition to the Baltic provinces, 327 



not visit this island, but saw a collection from these rocks in the 

 cabinet of Herr E. von Wahl. 



The best locality for excellent fossils of this formation is without 

 doubt the one which is taken as the type. This is near St. Johannis 

 church on the northeast corner of Oesel. About a mile southeast of 

 the church the rock is a compact, crystalline dolomitic limestone with 

 hardly any fossils. Beneath this lies a somewhat softer dolomitic 

 limestone in which are many large corals, belonging to Clathrodictyon, 

 Favosites, Halysites, and Syringopora. These beds probably corre- 

 spond to some part of the upper beds of Mustel Pank and Moon. 

 Underneath are the strata of St. Johannis church, consisting of white, 

 porous, marl-like limestones. Directly at St. Johannis the rock is not 

 seen in place, but blocks are not uncommon on the shore, and about a 

 mile northwest it forms a cliff. It yields readily to the action of water 

 and, since the fossils are more resistant than the inclosing rock, they 

 have not been destroyed; but concentrated on the beach. Where ex- 

 posed northwestward there is a cliff about ten feet high with the marly 

 limestones quite thick-bedded and bedding not well defined. Fossils 

 are not so common as at St. Johannis, as here there has been no con- 

 centration. 



There is no place in all the Russian Baltic where fossils are so 

 abundant and so beautifully preserved. Species which have been 

 collected at St. Johannis are: — 



1. Hindia fibrosa. 



2. Campophyllum irregulare Dybowski. 



3. Cystiphyllum cylindricum Lonsdale. 



4. Favosites gothlandicus. 



5. Halysites escharoides. 



6. distans. 



7. exilis. 



S. Ptychophyllum patellatum. 



9. Vincularia nodulosa. 



10. Atrypa reticularis. 



11. Camarotoechia bidentata. 



12. Cyrtia exporrecta (Wahlenberg). 



13. Dalmanella elegantula. 



14. Dinorthis rustica osilensis. 



15. Eospirifer radiatus. 



16. Meristina tumida. 



17. Leptaena rhomboidalis. 



