170 Reviews — O. Lindstrom — A Silurian Fish in Gotland. 

 12, IB "V I E ^W S. 



I. — On the Discovery op Cyathaspis in the Silurian Formation 

 OF Gotland.^ By G. Lindstrom. Communicated to the Eoyal 

 Swedish Academy of Science, December 12, 1894. 



FOR some years past drainage works have been carried on in 

 the marshy tracts of Gotland, and in most cases it has been 

 necessary to excavate wide and deep channels in the beds of lime- 

 stone and shale to carry off the water. In this way not only have 

 many instructive sections been laid open to view, but also manj'' 

 very productive localities for fossils, more particularly since through 

 weathering the excavated rock falls to pieces and sets free the shells, 

 which, as a rule, are not very firmly enclosed. 



During this last summer one of these canals has been constructed 

 in the village of Lau, on the south-east coast of Gotland. It is 

 nearl}' half a mile in length, and reaches from the plateau north of 

 the church down to the shore of the Baltic. For the greater part 

 of this distance it passes through marl shales of a more than usual 

 soft character. These shales rest below the limestones which form 

 the knolls round Lau chui-ch, so well known from containing the 

 operculate corals of the two species RhizophyJlum GotUindicum and 

 B. elougatum, together with other well-preserved fossils, some of 

 which are present in the underlying marl shales, which also are 

 rich in organisms. A peculiarity of this fauna is that all the 

 shells occurring in it are extremely thin, whilst the same forms from 

 other localities have thick shells. Moreover, they do not show 

 any indication of having been rolled in water. This circumstance, 

 together with the fine character of the shale, points to a considerable 

 depth of water, in which the animals lived bej'ond the influence of 

 wave action. The deposit may also have been formed in the still 

 water of a sheltered bay, for the almost entire absence of corals, 

 elsewhere so numerous, indicates under any circumstances smooth- 

 water conditions. 



Altogether, up to the present time, I am acquainted with about 

 fifty species from the marl shales of this canal. Of Crustaceans we 

 know a Calymene, Bumastus sulcatus, Proetas conspersus, an Eury- 

 pterid, a Ceratiocaris, and some forms of Lepeiditia and Beyrichia. 

 Of Cephalopods, some forms of Ortltoceras and a GompJwceras. Of 

 Annelids, Trachydeima ; four forms of Connlaria. several Gasteropoda, 

 with about eight Lamellibranchs and Brachiopods. Through such 

 species as Proetus conspersus, Avicidopecten Danbyi, M"Coy, and 

 others, the fauna of the Lau shales shows its relationship to the 

 other South Gotland faunas, such as the oolite and sandstone of 

 Bursvik, but it has also a faunistic connection with the Ostergarn 

 beds. 



An inhabitant of Visby, Mr. A. Florin, who has for the last twenty 

 years collected fossils for the pal^ontological section of the National 



1 Ofversigt af KoBgl. Vetensk.-Akad. Forliandlingar, 1894, No. 10, Stockholm, 

 pp. 515-518. Translated by Dr. G. J. Hinde. 



