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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. 
rs exilis. 
8. 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. 
