MODE XIV. SILICEOUS GLUTENITE. 



mon in Thuringia and in Magdeburg. 4. Red 

 grit, which is of a coarse grain, and the particles 

 united by iron. This is the de <dlaver of the Ger- 

 mans, which it is ridiculous to class here, as it 

 totally differs from his introductory definition. 

 5. Flexible grit of Brazil. 6. Filtering-stone, full 

 of numerous and irregular pores, but seemingly 

 composed of quartz only. It is found in Saxony, 

 Bohemia, New Spain, and the Canaries : it is also 

 found in Spain, in Guipuscoa, where they make 

 statues with hollow heads, so that water being 

 poured it passes through the eyes, and the figures 

 seem to weep. 



Such, he says, are the principal varieties afforded 

 by grit or sand-stone, considered as homogenous, 

 and not as a mingled rock; and he adds some 

 examples of sand-stones originally crystallised 

 with that texture : but when he includes the red 

 ferruginous sand-stone, he forgets that it some- 

 times contains fragments of porphyry and other 

 rocks ; and parts of the remainder of the article 

 refer to argillaceous and even calcareous sand- 

 stone. This stone therefore, which he places be- 

 tween quartz and flint, ought to have been classed 

 with the former under the usual denomination of 

 granular quartz. 



Mr. Jameson has observed*, that there is a 



* Geog. p. 39. 



