196 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Dubowiki formation. C, (Upper Linsenschicht and lower part of 
the Echinosphaerites limestone), of Schmidt. 
This formation, like the Kunda limestone is best exposed at the 
east, where it reaches its best development on the Walchow River at 
St. Michael Archangel, opposite Dubowiki, just above the steamer 
landing and below the railroad bridge. At this locality the base of 
the formation is not seen, but fourteen feet of soft caleareous mudstone 
are exposed, the base twenty-three and one half feet above water level 
in the river. This outcrop is capped by twelve feet of the harder 
dolomitic limestone of the Reval formation. Schmidt and Lamansky 
state that the upper part of B,,, (the Kunda formation) is to be seen 
in the basal parts of the quarries at St. Michael Archangel, but I was 
not able to find it, and so did not see the contact between the two 
formations here. The upper part of the Kunda is, however, exposed 
along the riyer bank about a mile below the steamboat landing and 
with the prevailing low dip should still be above the water-level at St. 
Michael Archangel. The thickness of the Dubowiki at this locality 
is therefore uncertain. It can not be more than thirty-seven feet or 
less than fourteen feet in thickness, and is probably twenty-five to 
thirty feet, as Dubowiki fossils, which seemed to be in place, were 
found within ten feet of the water’s edge. 
Schmidt and Lamansky agree that there is no “Linsenschicht”’ at 
the boundary between B,,, and C, at this locality. Following the 
Dubowiki westward it is present at various sections, but always 
thinner than at the typical locality. It is well exposed in the cement 
quarry and on the railroad south of Asserien, where it is fifteen and 
one half feet in thickness. It is here a hard compact limestone, 
unlike the soft marly beds at Dubowiki; and at this locality, as well 
as at Ontika and all the other localities in Esthonia the “Upper 
Linsenschicht”’ is present at the base of the formation. This linsen- 
schicht is not a definite, rather thin band, like the Lower Linsenschicht, 
but the linsen are smaller, less abundant, and scattered through a 
thickness of six or seven feet. Continuing westward, the Dubowiki 
formation thins out entirely, so that at Reval the upper Linsenschicht 
is reduced to a thickness of one foot and at Baltishport to ten inches, 
and it is at the base of the Reval formation instead of the Dubowiki. 
The Upper Linsenschicht is therefore a tangential formation and 
represents the invading base of the Wierland group. 
The fauna of the Dubowiki retains some survivors of previous 
faunas, though very few species are common to this formation and 
those below. This formation is particularly marked by the intro- 
