( 509 ) 
very well with those limestones as regards the principal features, 
though they are not interchangeable with the latter. More perfect 
still is the correspondence of our dolomites with the sample from 
Pantifer. From this it appears sufficiently that we have to look for 
the origin of our boulders in the eastern-baltic zone. Besides all 
authors agree about this question. Of course we do not mean to say 
that these Groningen erratics must of necessity originate in the zone 
now known. As the Borealis-bank is also found in Dagö, it may be 
surmised that it stretches, or formerly stretched, still farther westward 
under the sea, and the very uniform petrographical character of the 
rock throughout Esthonia leads us to adopt the opinion that this sub- 
marine continuation may also be considered as the possible place of 
origin of our boulders. Of course it is impossible to indicate a definite 
point in this zone, 
30. Elegans-limestone. 
With this term, referring to one of the most important fossils of 
this species of boulders, I denote a erystalline-limestone, generally 
fine-grained, sometimes almost impalpable, but still oftener rather 
coarse-grained. Calcite, bright as water often occurs rather regularly 
spread through the stone, but not in large quantities. The limestone 
is not perceptibly dolomitic nor marly, as in the solution in nitric 
acid only a small part is left and this solution produces no or hardly 
any reaction with magnesia. Its colour is bright-gray, sometimes 
rather yellowish-gray, rarely blewish-gray ; when weathered, however, 
the stone shades from white to yellowish white. Its surface is very 
often marked by distinetly visible glacial scratches. Layers are but 
seldom perceptible and moreover not very distinct. Fossils are by 
no means rare, but belong to a relatively small number of species, 
which are mentioned here : 
Phacops elegans Sars and Borek sp. 
Leperditia Hisingeri Scar. 
Strophomena pecten L. 
Vincularia nodulosa Erenw. 
Vineularia megastoma Ercnw. 
Enerinurus punctatus WAHLB. 
Calymene sp. 
Orthoceras sp. 
Proetus sp. 
Ptilodictya sp. 
Beyrichia sp. 
Murehisonia sp. 
