an 
WEDNESDAY, JUNE 14rx, 1893. 
At the close of the Annual General Meeting an Ordinary Meeting 
was held, at which a Paper was read entitled 
DISCOVERY OF THE REMAINS OF GYPS 
FULVUS IN A VOLCANIC DEPOSIT 
NEAR ROME: 
BY 
DR, E. J. MILES (of Rome). 
About 20 miles from Rome rise the Alban Hills, surmounted 
by Monte Covo, 3,127 feet above the sea. At the beginning of 
the Pleistocene period the site of these hills and the whole of the 
Roman Campagna was covered by the sea to the foot of the 
Apennines. Then, according to some geologists, began that series 
of submarine volcanic disturbances which resulted in the formation 
of a layer of tufa on the pleistocene sea-bed accompanied by a 
slow upheaval. After an interval, during which the dry land 
portion became occupied by animal and vegetable life, another 
volcanic eruption,aerial in character,took place, whereby a second 
layer of tufa was formed on the top of the other. The first layer 
is hard and compact, the upper one “ tufo granulare ” much softer. 
From the surface of this so-formed undulating plain arose the 
volcanic group of the Alban Hills. The lakes Albano and Nemi 
occupy the craters of two of the larger of these old volcanoes. 
Of the rocks evolved in these eruptions two kinds may be 
specially noticed, a leucitic lava, and a peperino. A mass of the 
former rolled across the Roman Campagna to within three miles 
of the City, and from earliest times has been much used for 
paving stones, &c. Peperino is a greenish grey fragmental rock, 
with interspersed crystals of Augite, Leucite, Biotite, Magnetite, 
&c. According to Panzi it was largely formed out of a volcanic 
ash by the aid of torrents of water. 
Impressions of grasses, &c., are found in its beds, which 
shows that its temperature was not high. A few months ago in 
