MODE XIV. SILICEOUS GLUTENITE. 



vens, so different is their nature from every thing 

 found in the environs."* 



The same able observer describes. 4 957, the Triumphal 



arch. 



triumphal arch of Augustus, at Aosta, as con- 

 structed of large squares of a singular kind of 

 pudding-stone, or large sand -stone, being an as- 

 semblage of fragments, mostly angular, of all sorts 

 of primitive rocks, quartzy, slaty, and micaceous, 

 the largest about the size of a hazel nut. The 

 cement he does not mention. Most of the ancient 

 edifices of Aosta and its environs are of this stone, 

 and the common people are persuaded that it is a 

 composition, as was also the first general belief 

 concerning granite; but Saussure observed the 

 rocks in the mountains on the north, above the 

 road to Yvree. 



Aspect 1. Green universal bricia, from the old 

 Egyptian monuments. 



The celebrated sarcophage, in the British Mu- 

 seum, is of this stone. As it chiefly consists of 

 green jasper, it may perhaps more properly be- 

 long to the Siderous Glutenites. 



The same, from the Valley of Cosseir. 



Aspect 2. The same, with rolled granite and 

 angular fragments of porphyry, from the same, 



* Sauss. 717. 



