14 G. LINDSTRÖM, ON THE SILURIAN GASTROPODA AND 1'TEROPODA OF GOTLAND. 



Brought forward 140. 

 MoUusca 



Cepli.ilopoda aboiit 100 



Pteropoda 5 



Gastropoda -. 174 



Lamellibranohiata about 80 okq 



Molluscoida 



Bryozoa about _ 50 



Bracliiopoda - 150 .-jqq 



Echinodermata 



Asteroidea 2 



Ecliiimidea - 1 



Criuoidea ._ — 180 jgg 



Ånthozoa about 100 



Graptolitce - - - 5 



Spongice -- 10 



Dubious organisms (Algse probably) and others 5 



TentaculitcB about — 5 



Total 1,007 speoies and varieties. 



It is to be observed that the munber of species in some groups has been rated 

 somewhat low and that in all probability a detailed research will considerably increase 

 it. As it now stånds we see that the Gastropoda vie in numerical strength with such 

 large groups as the Crinoidea and surpass all the others. 



The minor details in the distribution, geographical and geological, of the Ptero- 

 poda and the Gastropoda may be learnt from the annexed lists ^), in which first the 

 chief localities or local regions are given in 27 columns, and then in the six last columns 

 a summing up of their stratigraphical distribution. Under the headings of the loca- 

 lities, n signifies the lowest stratum, shale or sandstone, h the intermediate limestone 

 or the oolite, c the upperraost limestone. When a species is recorded as found only in 

 a and c this has beeii considered equivalent to its having been found in b also or in 

 all strata. 



As to the nanies of the localities, it should be borne in raind, that some of 

 them are intended for a small district around a central point. Thus Hall chiefly 

 means the strata c in the canal near Westös, but also the strata near the shore and 

 at Halls huk. Wialmsudd includes the adjacent shores of Fårösund, as the strata of 

 Sandvik, Gothem and Bara embrace chiefly the shore deposits at Gothemshammar and 

 a number of quarries opened westwards in the direction of Bara, where a little hill, 

 Bara backe, contains the same fossils. Linde and FarJliem comprises not only the lime- 

 stone hills there, but also the marly and gritty shales. 



The limestone beds of Samsugn in Othera, those of Wialmsudd and Wisby as 

 well as others are very rich in shells of Gastropoda intermingled with those of Cepha- 

 lopoda. But all these localities are by far surpassed by the limestone of Sandarfve 

 kulle. This is one of the small hills, which in the central part of Gotland, a little 



^) See page 16 and the following. 



