TweENnHOFEL.— Expedition to the Baltic Provinces. 
PLATE 3. 
Fig. 1— Contact between the Jérden Schicht and the Pentamerus borealis 
banks at Jorden, Esthonia. The type-section. | . 
The hammer is on the line of division. The spots in the upper 
strata are the shells and molds of Pentamerus borealis. 
Fig. 2.— Quarry face in the Raikiill formation at the type-locality in Esthonia. 
ein. 
