SKETCH OF 4GINA AND METHANA. 159 
The whole line is an excellent example of a petrographical 
province, the prevalence of hypersthene and colorless augite, 
and probably also the predominance of bytownite and anorthite 
among the feldspars, with absence of orthoclase; being some 
of the characteristics. But much work remains to be done in 
this direction along the whole line before we can feel justified in 
describing it. 
The mineralogical and petrographical characters of the 
Santorini lavas are so well known that nothing further need be 
said of them here in this respect ; but from a chemical stand- 
point, while they were examined with great care by Fouqué, yet 
many of the analyses are so unsatisfactory, and they cover such 
a small number of the various occurrences, that our knowledge of 
them is still very incomplete. 
From the short and not very detailed descriptions of Ehren- 
burg and Roth, cited above, it would seem that the augite, 
hypersthene, and hornblende-andesites of the Milos group Closely 
resemble those of A’gina-Methana, even in small details such as 
the occurrence of the hypersthene, glass ‘‘net-work”’ inclusions 
in the feldspar phenocrysts, rose color of the quartzes, and so 
forth. Unfortunately Ehrenburg does not mention the color of 
the hornblende of the hornblende-andesites, and no information 
is vouchsafed us by either author as to the chemical composition 
Ob the TOCks.,. 
Again, Nisyros, since it was visited by Ross* in 1841, who 
spent two days there and gives a short account of it, seems never 
to have been visited, and certainly never described by a geologist. 
When Ross was there it was in a solfataric state, and he describes 
the crater, the lava streams flanking the mountain and form- 
ing promontories in the sea. He speaks of the lava as black and 
mentions much ash and pumice as strewing the surface of the 
ground, but from his account we can form scarcely an idea of 
the petrographical character of the rocks of the island. 
In the course of some excavations at Platza in Beeotia in 18890, 
however, I found fragments of large corn-grinders made of a 
tRoss: Reisen auf den Griech. Inseln. Stuttgart. Vol. II. 1843, pp. 68-80. 
