ITALY. LETTER XI. I2p 



Herculamum have been covered with afhes, at 

 prefent petrified, and have been built of tufo -, which, 

 together with three different lava beds, found 

 by digging under the foundation of thefe cities, 

 and in the palace-garden at Portici^ give an idea 

 of the high antiquity of the former eruptions. 

 This yellow- brown tufo is frequently dug out near 

 Naples, and commonly employed in buildings; 

 which, for that reafon, are much fubject to decay. 

 The grotta di Paujilippo is cut through fuch a 

 hill ; and fideways, to the right, are quarries where 

 this tufo is cut into convenient fquare forms. 

 Such are too at Puzzuolo, and behind the Cata- 

 combes of 6'. Januario, or the ancient burying- 

 place-, where* by long excavations, have been 

 produced enormous caverns, even more dreary 

 and confiderable than the Catacombs occafioned 

 at Rome by the fame operations. 



In this tufo are now and then fourtd inclofed 

 fome adventitious bodies; which, by earthquakes, 

 or other accidents, have been buried therein : 

 fuch as, fome calcined (hells, acorns, chefnuts 5 

 and, if they have told me right, iron fcifTars, and 

 bones, and fkulls of animals. But that happens 

 very feldom, and there have never been found in 

 the alhes any confiderable quantity, or beds of fea- 

 fliells. They contain very often copious quanti- 

 ties of white garnet-like globulous polygone fherl- 

 K cryflal- 



