TIIK I'l.KlSTorKNK SKI; IF.s 



813 



in tin- seas round the nortln-ni parts of mir islamU, tin- species 

 of <>m southern coasts being generally absent. The following 

 an- Miiiu- of tin- coniiiioiuT species in Glacial Beds, and some of 

 tin-in an- shown in Fig. 201 : 



Hilda. Natica afnnis (clausa), N. pallida ( = groenlandica), Trophon 

 clatliratus, T. Fabricii, Bnccinuin undatutn, B. green- 

 landicum, Bela turricula, Turritella comraunis, Scalaria 

 green land ica. 



Fig. 201. GROUP OF PLEISTOCENE MARINE SHELLS. 



a. Pccten islandicus. 

 ft. ABtarte boron 1 is. 

 c. Corbicula fluininalis. 

 rf. Trophon Falmrii. 



-. Xatica aftinis ( = clausa). 

 /. Trophon clathratus. 

 'i. Scala grocnlandica 

 It. I'uncturella rioachina. 



I Hbranchia. Pecten islandicus, Leda truncata, Yoldia arctica, Y. 

 lanceolata, Tellina lata, T. balthica, Astarte borcalis, 

 A. compressa, Panopaea norvegica, Saxicava rugosa, 

 Cyprina islandica. 



B. GLACIATION AND GLACIAL DEPOSITS 



Griacial Deposits. These are the relics of a time when the 

 conditions which are now routined to the Arctic and Antarctic 

 legions prevailed over the whole of Northern Europe. They are 



