(513) 
found there everywhere, though they oecur in the Estomus-zone as 
well (8, p. 43). 
Encrinurus punctatus Wane. 
is only present in a single piece and is a fossil found in all Upper 
Silurian regions throughout all zones so that this species is of no 
value for the determination of the age. 
If we take these results together we get: 
Esthonia. Gothland. 
Phacops elegans Sars and Borek. GC, — H a—b. 
Leperditia Hisingert Scumipr. Gas Gs be. 
Strophomena pecten L. Gs e—h. 
Vincularia nodulosa Eicuw. G,—H 
Vineularia megastoma Ercuw. G,—H 
It appears from this distinctly, that these boulders are remains of 
an equivalent of the Raiküll zone G, in Esthonia. As to Gothland, 
the comparison with Lixpstrém’s zone 6, if a comparison is desired, 
is the most probable one. 
Moreover this result is especially interesting, because boulders of 
this age are not known in literature that I know of. In the Groningen 
collection on the other hand some pieces have been brought to this 
zone long since. But once NorrLinG mentions a stone belonging to 
this stratum which, however, contained no determinable fossils and 
was only under reservation by reason of the great correspondence 
to a piece of limestone from Raiküll, counted as a representative of 
this zone (9, p. 291). Roemer doubts of this (13, p. 77). 
As regards the origin of these boulders, it may first be stated, 
that none of the regions where only one or a few of the fossils 
characteristic of this occur, viz. Norway, (Scania), Dalarne and Jemt- 
land, can be taken into account. Besides the petrographic nature of 
these deposits precludes this supposition altogether. In Gothland on 
the contrary these fossils, with the exception of the two bryozoa- 
species, are all found. But the rock occurring there (almost always 
shales) does not show petrographically the least correspondence with 
our limestone. In fact these boulders must not be considered to origi- 
nate in Gothland. 
Lastly as regards Esthonia: The Raiküll zone, G,, (8, p. 43) 
extends from Laisholm in Livonia and Wahhoküll in East-Esthonia 
westward as far as Dagö; in the eastern part the zone is wider and 
