152 The Volcanic Rocks of 



reous ash, so common in Albano, is equally plentiful 

 with us. 



There is a great extent of territory covered with ash in 

 the old Roman States. The sea-board of the Campagna beds 

 extends ninety miles, while the breadth from hills to coast is 

 about twenty-tive. The Campagna in Rome, though a plain, 

 is not without many undulations. The soil is very fertile. 

 Once sparkling with a hundred cities, it is now almost a 

 desert. Kegiected culture has left undrained marshes to 

 breed the dreaded malaria, which now reaches the walls of 

 Rome. Let us hope that better days will see the tufa- 

 fields of Rome covered with good farms and a healthy 

 people. 



The ash on the Victorian plains is darker than that of the 

 Campagna, and niore generally of the granolare than the 

 lithoide character. Around the extinct craters, and on the 

 plains at their feet, the formation reposes. To the south and 

 west of Lake Corangamite and Lake Colac, many such spots 

 may be seen ; and so, also, passing from Ballarat to Port- 

 land, or Portland to Warrnambool. Excepting a few places, 

 as Mount Franklin, little tufa is found upon our diggings. 

 The later convulsions southward and westward have arisen, 

 doubtless, since the auriferous period. Tower Hill, between 

 Belfast and Warrnambool, shows the largest extent of this 

 singular mineral, affording the finest farming land in the 

 colony. A paddock of fifty acres of Mount Gambler ash 

 soil has this year averaged fifty bushels of wheat to the 

 acre. 



The depth of the ash of Rome is considerable, and even 

 greater than that which covered up Pompeii. In our colony 

 it has been frequently found one hundred feet. At Wood- 

 ford I observed great masses. It is ninety feet near Tim- 

 boon. By Tower Hill, the bank is thickest on the eastern 

 side, owing to the prevailing westerly breezes carrying the 

 ash away. On the north side, a farmer, a quarter of a mile 

 from the crater, told me it was eighty feet. Another, a mile 

 off" on the eastern side, sank one hundred and fifty feet in it 

 for water, and gave up the work. Around Mount Gambler, 

 the tufa varies greatly. In one part I saw it at least two 

 hundred feet thick, but found it run out on the north side in 

 a quarter of a mile. On another side, at an equal distance, 

 it was forty feet. The Ash Peak rises hundreds of 'feet 

 high. On the Pejark Marsh, between Mount Noorat and Lake 

 Keilambete, it is evenly distributed. The tufa of Lake 



