﻿680 SUMMARY OF THE CONTENTS. 



investigations of the author, about 30 occurrences are now known 

 (see p. 669) with 25 species of mollusca, etc. 



It is proved that in Southern Norway the yoldia clay occurs 

 exclusively outside the ra; the occurrences known are distributed 



along the south coast, from the frontier of the kingdom 



in the east to the island Jomfruland (p. 667), where the ra 

 crossas the sea in the form of a long barrier outside the coast. 

 The yoldia clay is the fine silt and mud, deposited by the water 

 melting from the ice in front of the land-ice. The main occur- 

 rences of the yoldia clay of the Kristiania region are indicated 

 on the map, p. 28, by dark round spots; they are enumerated 

 on p. 669. 



Pp. 31—54. The Fauna of the Yoldia Clay. 



The moUuscfauna of this clay comprises the following 26 

 species and a number of varieties of the same: 



peden islandicus, Mtill. ; modiolaria nigra; Gray; * port- 

 landia arctica, Gray; var. siliqua, Reeve, var. portlandica, 

 Reeve, var. inflata, Leche, var. nux., W. C. B.; yoldia hyper- 

 horea, Loven; * leda pernula, Miill. & var. costigera, Leche; 

 nucula tenuis, Mont., var. expansa, Reeve; macoma calcaria, 

 Chemn. & var. maxima, W. C. B.; lyonsia arenosa, Møll.; 

 saxicava arctica, Lin. & var. uddevallensis, Forb.; lepeta coeca, 

 Miill. & var. major, W. G. B.; natica af finis, Gmel., var. 

 dansa, Brod & So w; lunatia gronlandica, Beck.; hela nohilis, 

 Møll. (6. rugulata, aut.) *; admete viridula, Fabr.; buccinum 

 terræ novæ, Beck, var. grandis, W. C. B. & var a, Morch, 

 Leche; buccinum hydrophanum, Hanck. var. data, Friele, & 

 var. fuscorufescens, Poss. & var. texturata, Poss. ; neptunea 

 despeda, Lin. & var. carinata; neptunea densdirata, n. sp.; 

 volutopsis norvegica, Ghemn. (conf. p. 666); sipho togatus, 

 Mørck & var. Pfaffii, Mørch & var. sinuosa, W. G. B., & var. 

 vallensis, W. G. B. ; sipho hrevispira, n. sp. ; sipho islandicus, 

 Ghemn.; sipho Verkriltseni, Kobelt var. plicifera, W. G. B.; 

 trophon truncatus. Strøm & var. major, W. G. B. *; cylichna 

 Reinhardti, Møll. Mørch. * 



