298 Prof. Necker on the History and Progress of Geology . 
already a series of Volcanic rocks, distinguished from the Neptu- 
nian rocks, ranges in chronological order, side by side, with 
the tertiary and secondary formations. But, ought we to stop 
short here, and are there not, equally with the transition rocks, un- 
stratified crystalline masses, which require to be separated from 
the strata containing shells, or those of fragmentary or brecciated 
composition P We have said elsewhere, and we repeat it here 
with more confidence, that u the formations of basalt, trachyte, 
porphyry, and granite, to whatever period they belong, and 
whatever be the deposits which they accompany, or which they 
traverse, have certain common geological characters, which se- 
parate them from the regularly stratified shelly formations. 
These formations are, as it were, separated links of a great chain, 
which is attached by one of its ends to the volcanoes.” To the ob- 
servations made in Scotland, which have already appeared to us de- 
cisive, further confirmations have been added from other quarters : 
thus rocks evidently volcanic have been seen intimately associated 
with transition syenites and porphyries, by Humboldt in Mexi- 
co, and Beudant in Hungary. Mr Boue has seen, in the Hartz, 
and in the neighbourhood of Freyberg itself, in those mountains 
of the Erzgebirge which were the object of Werner’s particular 
study, porphyritic and granitic masses, similar to those of Scot- 
land, and bearing evident marks of their posteriority to the rocks 
which they traverse, I had almost said of their elevation from 
beneath. Lastly, Yon Buch has observed, in the Tyrolese Alps, 
analogous phenomena so striking, that he is induced to conclude, 
that the elevation of the mountains is a natural consequence of 
the protrusion of these enormous masses of porphyry. I delight 
to recal here the recital of these remarkable observations, which 
I have had the good fortune to hear from the very mouth of 
that illustrious geologist, in the mountains of Carinthia and Car- 
niola, where phenomena, similar to those of the Tyrol, although 
less evident, are still observed. 
These are the victories gained by observation over hypothesis, 
these the numerous results which the remains of the old specu- 
lative spirit had so long concealed from the view of naturalists. 
Let us continue, therefore, to follow that method, the only wise, 
the only profitable and truly philosophical, which patiently col- 
