238 
IGNEOUS ROCKS. 
The principal communication we have received on rocks of igne- 
ous origin has been from our Secretary, Mr. W. I. Hamilton, who has 
read an interesting paper on the north-west part of Asia Minor, from 
the Peninsula of Cyzicus to Koola, with a description of the Kata- 
kekaumene. Between Cyzicus and Koola the principal stratified 
rocks are schist, with saccharine marble, compact limestone resem- 
bling the scaglia of Italy and Greece, tertiary sandstones, and tertiary 
limestones. The igneous rocks are granite, peperite, trachyte and 
basalt. The tertiary limestones are referred to the great lacustrine 
formation which occupies so large a part of Asia Minor. Hot 
springs burst forth near Singerli from a porphyritic trap rock. The 
Katakekaumene is a volcanic region, extending about seven miles 
from north to south, and from eighteen to nineteen east and west. It 
presents two systems of volcanic craters and coulées: the older of 
them are placed on parallel ridges of gneiss and mica slate, and the 
newer in the intervening valleys; hence he argues, that when the 
latter eruptions took place, the lines of least resistance to subter- 
raneous expansion were in the valleys. The streams of lava from 
the more recent cones are bare and rugged, like the coulées in cen- 
tral France. Three periods of eruption are traced: the first, ha- 
ving produced basalt, which caps the plains of white limestone, and 
was ejected before the formation of the valleys; the second, marked 
by currents of lava from the more ancient system of volcanos in 
action since the formation of the valleys; the third resembling the 
coulées of Etna and Vesuvius, and mentioned by Strabo, but of 
which there is no historical tradition as to the period when they 
were in activity. 
We have a notice by the Rev. W. B. Clarke of a shower of ashes 
that fell on board the Roxburgh off the Cape de Verd islands in 
February, 1839, the cause of which ‘was not apparent. ‘The sails 
were covered with a fine powder, resembling the ashes of Vesuvius, 
which was probably derived from an eruption in the Cape de Verd 
group. 
PALEONTOLOGY. 
In the department of Palgontology Prof. Owen has, during the 
past year, contributed many papers, with his usual zeal and ability, 
