KONGL. SV. VET. AKADEMIENS IIANDL. BAND. |9. N:0 6. 33 



It must have been in some sheltered bijijhts, where a calcareous mud found stillness 

 enough to allow it to settle down, that such deposits as the fine grained limestone of 

 Sandarfve, or Samsugn with tlieir numerous and beautifully jjreserved shells originated. 



In general the shells were middle sized, only a few, as Pleurotomaria valida, 

 or PI. cirrhosa attaining a greater size. Fragments of an undeterminable shell from 

 the shale of Gnisvi'ird attain in the height of the body whorl alone 82 mm. and in 

 breadth 9S mm., this being the largest fossil shell, known in Gotland. This size and 

 the comparative rarity of tiny shells also militate against any assumption of great 

 depth for these forms, as only small sized species have been dredged up from the 

 abj'ssal depths. 



2. Tlw faunn had a tropiral rharacter. In consideration of the great numbers 

 of Pleurotomariae, Trochi, Turbinida? and the large Pteropods the assumption of a 

 tropical character of the fauna may seem justifiable. 



Older descriptions of Gotland Gastropoda. 



There has been no want of workers in this field, as we ran learn by a review 

 of the memoirs of the authors previous to this. The first time any mention has been 

 made in print of the Silurian Gastropoda of Gotland was when Magnus von Bromell 

 published the "Articulus secundus» of his "Lithographia Svecanaw '). He there, pages 

 28 — 37, enumerates and summarily describes 21 different numbers of fossil Gotland 

 Gastropoda. But as both the descriptions and the figures are very unsatisfactory — 

 the originals being mostly mere nuclei — I have not been enabled with any degree of 

 certainty to identify more than a few. Thus N:o 5, page 30, and N:o 6, p. 31, in all 

 probability are specimens of Pleurotomaria alata. N:o 21, p. 30, is an Oriostoraa and 

 probably Oriostoma sculptum Sow. In N:os 2fi — 27 we see nuclei of Murchisonia> and 

 N:o 27 may be M. attenuata. 



LiNNiEUS has left no descriptions of any fossil Gotland Gastropoda. In the relation 

 of his travel on Gotland in 1741 he only mentions them in passing. On page 189 he 

 says: »!'etrificata plackades af oss hela tiniarna pa wastra Stranden (af Kapellshainn), 

 ibland hwilka woro ganska manga Conchitaj striatte och Cochlita^» . . . . i. e. ^Petrifica- 

 tions were collected by us for several liours on the western shore, amongst which 

 were a great number of Conchita^ striata^ and Cochlita^» . . . 



WiLHELM HisiNGEU began his long, honourable and meritorious activity as the ex- 

 plorer of the geology and palaeontology of Sweden so long back as in 178'.) at the early 

 age of 23 years with his first memoir and in 1798") he published "Minerographiske 

 anmarkningar ofver Gottland». On page 2S() he eniimerates with other fossils oidy a single 

 nTarhi)? i pisolit kalksten". In 180S »Samliiig till en mineralogisk Geografi ofver Sverige>' 

 was published and there he only recapitulates the remarks in the preceding paper. The 

 number of Gastropoda accepted by ITisingeu was raised to ten in his geological de- 



') In the oActa Litciiiiia et Srientiaiiim Svecia;», Vol. Ill, Upsala 1738. 

 '-) 111 the Transartions of the U. Swedish Ar. of Sciences. 



K. Vet. .\ka.l. It.iii.ll. B:inil 1^1 N;o i; 5 



