112 GEOLOGY. 



this volcano previous to the Christian era, although it 

 had the structure of a volcanic mountain. It had been 

 so long inactive that vines grew all over the interior of 

 the crater. In A.D. *79, after a series of shocks during a 

 dozen years previous, an eruption occurred which buried 

 up the cities of Herculaneum and Pompeii. There was 

 not much lava thrown out in this eruption, but chiefly 

 loose material, such as sand, ashes, cinders, and stones. 

 The steam which rose at the same time from the volca- 

 no, being condensed in the air, fell in showers, and, be- 

 ing mingled with the ashes and sand, currents of mud 

 ran into the streets, houses, and cellars, filling them up. 

 "Hence it is," says Hitchcock, "that when these cities 

 were first excavated, more than a hundred years ago, ev- 

 ery thing enveloped was in a most perfect state of pres- 

 ervation the pavements of lava, with deep ruts worn by 

 the carriage wheels ; the names of their owners over the 

 doors of the houses ; the frescoed paintings as bright as 

 though put on but yesterday ; fabrics in the shops still 

 showing their texture ; vessels of fruit so well preserved 

 as to be easily recognized ; bread retaining the stamp of 

 the baker, and medicine yet remaining on the apotheca- 

 ry's counter. The whole constitute perfect examples of 

 fossil cities." Some skeletons have been found incased 

 in tuff or tufa (porous volcanic rock), finely preserved. 

 Around the neck of one was a chain of gold, and on the 

 bones of the fingers were jeweled rings. Resina was built 

 over the buried Herculaneum, but this was destroyed by 

 a river of lava in 1631. In Fig. 44 you have represented 

 the appearance of the crater of Vesuvius in 1829. The 

 top of the volcano was blown off in 1822 to the extent 

 of more than 800 feet. 



196. Etna. This volcano, on the island of Sicily, is 

 about 90 miles in circumference, and is nearly two miles 

 high. In its eruption in 1669 its lava destroyed fourteen 

 towns and villages before arriving at Catania, and there, 

 although the wall was 60 feet high, it accumulated to 



