Chap. 48.] rOKMACEAN WALLS. 289 



at finding the most inferior constituent parts of it, known as 

 ** dust"'* only, on the hills about Puteoli, forming a barrier 

 against the waves of the sea, becoming changed into stone the 

 moment of its immersion, and increasing in hardness from daj- 

 to day — more particularly when mixed with the cement of 

 Cumae ? There is an earth too, of a similar nature found in 

 the districts about Cyzicus ; but there, it is not a dust, but a 

 solid earth, which is cut away in blocks of all sizes, and which, 

 after being immersed in the sea, is taken out transformed into 

 stone. The same thing may be seen also, it is said, in the 

 Ticinity of Cassandrea ;''^ and at Cnidos, there is a spring of 

 fresh water which has the property of causing earth to petrify 

 within the space of eight months. Between Oropus and Aulis, 

 every portion of the land upon which the sea encroaches be- 

 comes transformed into solid rock. 



The finer portion of the sand of the river Mus is not very 

 difi'erent in its properties from the dust of Puteoli; not, indeed, 

 that it is used for breaking the force of the sea and with- 

 standing the waves, but only for the purpose, forsooth, of sub- 

 duing**^ the body for the exercises of the palestra ! At all events, 

 it was for this purpose that it used to be brought over for 

 Patrobius,®^ a freedman of the Emperor liero. I find it stated 

 also, that Craterus, Leonnatus, and Meleager, generals of Alex- 

 ander the Great, had this sand transported along with their 

 munitions of war. But I forbear to enlarge any further upon 

 this subject ; or indeed, by Hercules ! upon those preparations 

 of earth and wax of which the ceromata are made, so much 

 employed by our youth in their exercises of the body, at the 

 cost of all vigour of the mind. 



CHAP. 48. (14.) FOEMACEAN WALLS. 



And then, besides, have we not in Africa and in Spain 

 walls*- of earth, known as "formaceoan" walls? from the fact 

 that they are moulded, rather than built, by enclosing earth 



78 "Pulvis," See B. iii. c. 9, B. xvi. c. 76, and B. xxxvi. c. 14. He 

 alludes to the cement made of volcanic ashes, now known as *' Pozzuo- 

 lane." '9 See B. iv. c. 17. 



80 It being the practice to rub the bodies of the athletes with sand. 



81 This circumstance is mentioned also by Suetonius, in his life of Nero. 

 Patrobius was slain by order of the Emperor Galba. 



82 Ajasson says that they are called tafias at the present day in Spain. 

 VOL. VI. U 



