272 GEOLOGICAL MEMOIRS. 



be seen, sparingly distributed through it. It appears in many- 

 places that the boulders of this sand are only the result of the dis- 

 integration of the boulder clay, the proportion of rocks of different 

 kinds being almost exactly the same ; and hence it results that the 

 current which formed this newer bed brought few or no materials 

 with it, merely reconstructing in a somewhat different form the 

 rocks over which it passed. 



The boulder sand contains, here and there, fossil remains of several 

 species, all of which are still common on the coast of the North 

 Sea. Near Svendborg in South Fuhnen, I met with Buccinum 

 reticulatum, and near Tarbeck in middle Holstein there is an 

 oyster bank where with Ostrea edulis are associated Cardium 

 edule, Littorina littorea, and Buccinum undatum. 



Just as the sandy plains and ranges of sand hills appear in 

 Denmark, they are also found in middle and southern Sweden, 

 and there they sometimes appear as thick horizontal layers of sand, 

 which by subsequent marine action have become converted into 

 chains of low hills ; and sometimes they form more decided and 

 higher hills, of which the great Aos, which extends from above Up- 

 sala to Stockholm, nearly parallel to the coast of the Gulf of 

 Bothnia, is an instance sufficiently remarkable from the undulating 

 appearance of the strata of which it is composed. 



Many sections, both on the coast and in the interior of Sweden, 

 exhibit the sequence of these beds. The clay, the base of these 

 sections, contains the Mytilus edulis, indicating the presence of the 

 sea at the time when the formation of the Aos commenced. Upon 

 the clay there rests a bed of sand exhibiting false undulating strati- 

 fication in layers 25° E., and then succeeds a horizontal layer of 

 small stones washed from other beds ; and lastly, vegetable mould. 

 Ibelieve there will be found sufficient proof that the Swedish Aosar 

 were all formed in the same manner as the Danish, and without 

 doubt, at the same period, and by similar agency. 



D. T. A. 



[M. Forchbammer then enters on the consideration of the various theories 

 that have been suggested to account for these phenomena. A notice of this 

 part of the paper will be given in the next number of the Journal. — Ed.] 



