(514) 
narrows westward. It almost always consists of two systems, now 
limestone, then dolomite. In the above-mentioned passage SCHMIDT 
gives no further petrographical description of the rock; but afterwards 
he speaks once more (33, p. 308) of a “dichten, festen, etwas kiesel- 
haltigen hellgelben Kalkstein, der demjenigen unsrer Raiküll’schen 
Schicht am meisten gleicht”. For want of material for comparison: 1 
dare not conclude from this a great correspondence with our lime- 
stone. Further it is striking that Scumipr says that petrifactions are 
comparatively rare in the Raiküll stratum, except corals. Now our 
boulders contain a comparatively great number of fossils, whereas 
corals are altogether wanting. Just the reverse argues the fact that 
graptolites occur in both, which though shortly described as Deplo- 
graptus estonus Scum. (2, p. 226), are not vet figured. Perhaps the 
same species may be found in our pieces. 
By reason of the differences adduced above, I deem it little probable, 
that the Raikiill stratum in Esthonia itself can be considered as the place 
of origin. It is not impossible that the submarine continuation of this 
zone consists of a rock more corresponding with our boulders. For 
the present this question cannot be solved more completely though 
material for comparison esp. from G, in Dagö, may render valuable 
services. 
LITERATURE. 
1. Roemer, F. — » Ueber holländische Diluvialgeschiebe’. 
Neues Jahrbuch fiir Mineralogie, etc, 1857, p. 385—592. 
2. Scmuprt, F. — » Untersuchungen über die Silur-Formation von Ehstland, 
Nord-Livland und Oesel’’. 
Sep.-Abdruck a. d. Archiv f. d. Naturkunde Liv-, Ehst-und Kurlands, le Ser., 
Bd. IL, Lief. 1, p. 1—248. Dorpat, 1858. 
3. Rormer, F. — »Versteinerungen der silurischen Diluvialgeschiebe von 
Groningen in Holland”. 
Neues Jahrbuch, etc, 1858, p. 257—272. 
4. Scrmpr, F. — »Beitrag zur Geologie der Insel Gotland, nebst einigen 
Bemerkungen ueber die untersilurische Formation des Fest- 
landes von Schweden und die Heimath der norddeutschen. 
silurischen Geschiebe’’. 
Archiv f. d. Naturk, Liv-, Ehst- und Kurlands, Ie Ser. Bd. II, Lief, 2, no. 6, 
p. 403—464; 1859. 
5. Ercuwatp, E. p’ — »Lethaea rossica ou Palaeontologie de la Russie”. 
Atlas. Ancienne Période. 
Stuttgart, 1859, 
