Roine and Victoria. 151 



material for submarine structures. I have examined the 

 Trass of the Brohl Valley, near the Ehine, which has the 

 same property. As we have not yet utilized our colonial 

 tufa, I am not able to say how far we may produce a Vic- 

 torian cement from that source. 



As th^Pozzolano was anciently called Arena^and obtained 

 from the vast masses of tufa around Rome, some have 

 erroneously supposed the catacombs to have been arenarice, 

 or sand-pits. I did not perceive any material difference 

 between the ash of the catacombs and that of Victoria. 

 Excavations could readily be made in our own, as the wom- 

 bats discover; and as the material will not hold water, it would 

 not be objectionable for a cemetery. The Italians term the 

 catacomb-stone tufa granolare. It is like ours, to use the 

 words of Daubeny, " dull and harsh to the feel, with an 

 earthy fracture." It appears not to be so rich in minerals as 

 the Peperino of Albano, which contains the garnet, nepha- 

 line, mica, Vesuvius angite, and dolomitic limestone. Dr. 

 Ciuxlie assured me he had detected much Vesuvianite in his 

 ash-banks by the Curdles river, towards Cape Otway. The 

 eruption occurring in a Limestone country would account for 

 the nodules of that rock found in the Roman tufa. I saw much 

 of it in the ash of Mount Gambler, the neighbourhood of which 

 is all limestone, and whose craters are hollows in that rock, 

 blo^\^l out or subsiding during the convulsion. 



Excavation in the tufa would afford admirable shelter. 

 The shepherds of Italy, to this day, find relief from weather 

 on the Campagna in the gi^ottoes dug out in the ash. The 

 ancient Etruscans used such for tombs. The Roman tufa- 

 beds afforded graves before the Christian era, even to the 

 Jewish colony of that city, though the catacombs became 

 eventually the honoured and revered property of persecuted 

 Christendom. As I stood in one of the dimly-Kghted 

 recesses, with my hand idly mingling the dust of mart3rred 

 loved ones with the ashes belched from a roaring crater, and 

 listened to a lecture by an Irish priest upon the recovery of 

 the bones of- St. Csecilia, beside whose grave we were 

 gathered, and whose anniversary of martyrdom was then 

 being honoured, I could not but feel how rich with sacred 

 and loving association was the tufa of Rome compared with 

 ours. 



There is a sort called Pisolitic Tuff, or Tufa. This 

 has balls, or shot-like pieces, supposed to have been pro- 

 duced by drops of rain at the time of the fall. The calca- 



