296 DOMAIN III. ARGILLACEOUS. 



lerius, the filtering-stone from the Canary Islands,, 

 and New Spain, consists of angular particles of 

 quartz, united without any cement ; but the pure 

 siliceous sand-stone seems the most uncommon. 



Gmelin, in the last edition of Linnaeus, has 

 included Cos among the Lapides arenarii, which 

 he rightly arranges in three divisions, with a sili- 

 ceous, calcareous, and argillaceous cement. Of 

 the latter he particularises that of Fahlun, in Swe- 

 den, where it forms the bottom of the copper- 

 mine ; and that found in many countries, where it 

 is used for slates. The sand-stone of Derbyshire 

 is chiefly argillaceous, as is probably the flag-stone 

 of Oxfordshire. To this class also generally be- 

 longs the sand-stone found in coal-mines, which 

 sometimes bears vegetable impressions. Some 

 sand-stones present layers of variegated colours, 

 the cement being probably argillaceous, tinctured 

 with iron in various proportions *. 

 Saussure mentions the following : 

 Argillaceous sand-stone, in vertical beds, or 

 arrects, which he says cannot be the effect of a 



* Mr. Jameson says (Dumf. 166) that the cliffs of Hawthorn- 

 den are of red sand-stone : argillaceous or siderous ? The same 

 question may be applied to the chain of mountains behind our set- 

 tlements in Notasia, or New Holland, which have been found im- 

 passable. Voy. de Peron, Paris 1808, i. 3Q3. From the sea to that 

 chain the radical rock is siliceous sand-stone. 



