( 571 ) 



eiTatic-l)l(K'ks ^vitll Ilvolitlius-i-eiiiaijis coiisiï^t, luis hccii described hv 

 this author as type a. The piece of hrown sandstone Avilh the valve 

 of a small Hrachio[)0(lo I found at IJoriihohn, belongs to his (vpcr/. 

 The fossil occurring in it has been determined by me as a vaulled 

 valve of Discinella Holsti Moberg. The erratic-block that was shown 

 me by Gottschk probably belong's to the sauie type; the organic 

 remains occui-ring in it ai-c likely to ha\-e couie fi-oin the same 

 species of Urachiopodes. 



The Hyolithus-remains in the Hemelum erratic-block have been verv 

 imperfectly preserved, ^vhich, according to Hot.m, ') is usuallv the 

 ease with this stone. A longitudinal section possesses a length of 10 

 millimetres and at the month a breadth of 4 millimetres, so the 

 dimensions of this shell remind of the one ])ictured and described 

 by jMoberg '^) under the name of Hyolithus Insularis nov. spec, 

 whereas Holm after\vard called it Hyolithus Confusus now spec. 



The relative age of this kind of erratic-blocks does not seem to be 

 Avith certainty known yet, as up to this time no corresponding stone 

 has been met \\'\{\\ as firm rock, and the organic remains found in 

 them have not yet been discovered in company with such as might 

 contribute to the solution of this question. Moberg, however, thiidcs 

 he ma} conchule from the general character of the fossils occur- 

 ring in them, from their petrograpliical nature and from the \\a\- 

 in ^^hich they are spread, that they come from Under-Cambrian 

 layers. 



HoLST •') draws the same conclusion, after tracing the manner iji 

 which they are spread. 1 think I may infer from his essay, that in 

 his opinion they come from the youngest Under-(^ambrian layers. 

 In accordance \\\\\i this is the presence of Discinella-remains, this 

 genus of Brachiopodes occurring, according to Mobekcj, in North- 

 America, in layers containing Olenellus. 



As was said just now, a corresponding kind of stone was not vet 

 met with as firm rock. Most probal)Iy it formerly occurred west- 

 ward of Oeland; it may be found there even now at the bottom of 

 the sea, because this kind of erratic-blocks is found in large num- 

 bers only on the \vestern coast of this island, between Halltorp and 

 Mörbylanga, and on the little isles and cliffs in the neighbourhood. 

 Less numerous they are in tiie other [)arts of the eastern and western 

 coasts of the Kalmarsund. 



1) Holm loc cit. p. 74. 



2) MoBEKG. Om en iiyupptiickl lauiia i Ijluck oi kaiulnisk sandstcii clc. p. 117. 

 •^) HoLST. Bidrag till ktinnedomcn om lagerföljdcn inoin den kambrlska sand 



stenen, p. 9. 



