twenhofel: expedition to the Baltic provinces. 319 



west of the village and railroad station, Tamsal. The rock is there 

 quarried for lime, an extensive plant being in operation. This is 

 taken as the type-locality of the zone, since Schmidt gives none, as 

 well as the type of the formation. About twelve feet of strata are 

 visible here, the basal two feet belonging to the Jorden beds and the 

 upper ten feet to the Borealis banks. 



The rock is a gray and >»'ellowish gray Pentamcrus borealis breccia. 

 No two valves were seen together and little else can be seen. Clath- 

 rodictyon is the only other common fossil. 



The rock at the Weissenfeld locality previously described (p. 317) 

 is not so exclusively composed of Pentamerus borealis, and entire shells 

 are not uncommon. At Helterma, on the island of Dago, the beds 

 outcrop on the beach and, as at Weissenfeld, the rock is not so com- 

 pletely a mass of Pentamerus, although parts are full}^ as much so. 

 Syringophyllum organum, Clathrodictyon vcsiculosum and other corals 

 are not uncommon here. This outcrop may represent the upper 

 portion of the division. The Korealis banks are also shown by eight 

 or nine feet in the Podrang quarry near Tamsal, and there the shells 

 do not make such a great proportion of the beds. 



From the localities cited it appears probable that only the lower 

 portions of this zone have been seen, unless the exposures at Helterma 

 lie above the base. Schmidt was inclined to believe that the Borealis 

 banks lose their character as a unit upon the island of Dago, reaching 

 this opinion from finding P. borealis in the Jorden beds at Kallasto. 

 This is by no means certain, as this shell also occurs in the Jorden beds 

 at Tamsal, and in some places it should be more abundant than else- 

 where in this basal division, and perhaps this is the case at Kallasto. 

 As a shell breccia, the division probably has only a local development. 



The fauna of this division has never been carefully studied. It is 

 probably not large, since the conditions of fossilization were not such 

 as to lend themselves to the preservation of delicate forms. The 

 omnipresent fossil is Pentamerus borealis. Syringophyllum organum, 

 Favosites gofhlandicus, Clathrodictyon vesiculosum, and small bryozoans 

 occur more or less rarely. 



(c) Raikull beds. This division is the thickest of the three belong- 

 ing to this formation, Schmidt stating that 100 feet may be present. 

 It appears to be continuous Math the Borealis banks, and receives its 

 name from Raikull, the estate of Count Keyserling. In general, the 

 rock is a coralline limestone, in some places completely dolomitized, 

 in others a mass of corals, and in still others well-bedded crystalline 

 limestone. The division makes its appearance about twenty miles 



