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not unfrequently, var. formosa less often. But the characteristics of 
these varieties are by no means conspicuous, so that there are 
specimens which partake of the nature both of these varieties and 
the real species, as CHMIBLEWSKI himself too has perceived. In 
accordance with this is the fact that these varieties are practically 
of no stratigraphical importance; it is on these grounds I have 
thought it allowable to combine all these forms in one species under 
the name of Leperditia baltica His. sp. 
It has been frequently found in boulders. Kinsow deseribes it from 
“weisslich-grauen Mergelkalk” of Langenau, from “ziemlich verwit- 
terter und in Folge dessen gelblich gefärbter Kalk mit zahlreichen 
Schalen der Leperditia baltica His. (Ff. Scrap); daneben finden 
sich Knerinurus punctatus, Alrypa reticularis, und einige schlecht 
erhaltene Beyrichien, u.s.w.’ from Zoppot-Olivaer Walde, also in 
West-Prussia. The first stone corresponds perfectly with limestone 
from Langers in the N.B. of Gothland, the second shows much 
correspondence with the occurrence of Oesterby near Slite. Therefore 
he refers these pieces to Gothland. (Of the co-occurrence of L. baltica 
His. sp. and “. Hisingert Scum., which question I treated of in my 
previous communication (33, p. 560), he is afterwards not quite 
sure — 19, p. 90). In his excellent, already frequently cited treatise 
CrumieLewski briefly deseribes six boulders in which he has found 
L. baltica in Kurland, Kowno, East and West-Prussia. Most cor- 
responding with our boulders seems to be his: “hellbräunlich-grauer, 
deutlich krystallinischer, wenig thoniger, fester, unebenbriichiger 
Kalkstein mit Anerinurus punctatus (80, p. 33),” from Kowno. He 
does not give a decided opinion about the origin. 
Farther to the west this species is still recorded from Brandenburg 
by Rramrú and Krauss, mostly together with fossils, which also 
occur in our boulders and from limestones which, so far as can be 
gathered from the short descriptions, correspond in some respects 
with ours. STOLLEY describes also various of those limestones from 
Sleswick-Holstein among which “ein gelber Kalk enhält neben 
L. baltica His, Atrypa reticularis L. und Enerinurus punctatus 
WAHLENBERG” is again conspicuous. From Groningen our species 
was already recorded in 1878 by Martin, from Kloosterholt after- 
wards also by Bonnema (29, p. 452). 
From these statements about the erratic occurrence of this species, 
it appears sufficiently, that it has spread from Kurland and Kowno 
to the Netherlands though nowhere, it is true, large numbers of such 
boulders have been met with. In the Seandinavian-baltie area it is 
found in different places in solid rock: 
