232, Dr. Cooper on Volcanoes 
No difference in appearance can be pointed out between 
the basalts of Saxony and Lavas, as has been before ob- 
served. 
No difference has been shewn in the chemical, or in-the 
mechanical characters of basaltic Lava, and basaltic floetz 
trap. 
Cordier’s paper on the substances that compose the mass 
of voleanic rocks of all ages, has shewn that augit, horn- 
blende, felspar, and titaniferous iron ore, are the compo- 
nent parts equally of fletz trap and of Lava-basalt. Journ. 
de Phys. Tom. 63. 
The more the fletz trap regions are examined, the more 
decided marks of former craters are discovered. Until the 
numerous craters in and about Rome were discovered, this 
voleanic region would have passed for a country covered by 
fleetz trap ; just as Auvergne yet is, notwithstanding the 
numerous craters of extinct volcanoes, traced and noticed 
by Soulavie and others. 
Itis impossible to account for the pores in basalt, but from 
the violent extrication of air, or steam while in a soft or 
fluid state, as we do for the pores in Lava: or for the carbo- 
nat of Lime, prehnites, zeolytes, agates, &c. that are formed 
in those pores, as we do for similar substances gradually in- 
filtrated and crystallized in the pores of Lava. 
The experiments of Sir James Hall, Mr. Gregory Watt, 
and Dr. Hutton, on Whin-stone, and Rowley Ray, ch fane 
the volcanic origin of these stones as they now appear. 
Hence then it appears, stated briefly, that 
Lavas | The Fletz-trap formation ; 
Contain as their greatest proportion,| Contains as its greatest propor- 
rocks not to be distinguished in any|tion, rocks not to be distinguished 
way ; from floetz trap basalts. from basaltic Lava, in appearance, in 
physical properties, or in chemical or 
ihe mechanical composition. ; 
They pass into and are accompa-| So are fletz trap Basalts. 
nied by porphyries, amygdaloids, and 
porous stones filled up by infiltrated 
minerals of various kinds. 
They are accompanied by granite, Such is the case also of fleetz trap 
gneiss, mica slate, sienite and other} basalt. See particularly Dr. M’Cul- 
primitive rocks of various sizes and in| loch’s paper on the Granite of Aber- 
various quantities. deen-shire, and his remarks on the 
sienite of the Scotch Isles. So, when 
Von Buch and Haussman were at 
| Christiana i in Norway, the exclama- 
‘tion was, sui’je en Auvergne. 
