cly PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
countries, finally end with the small species of PAzllipsia in the car- 
boniferous limestones. The memoir of M. de Verneuil, of which the 
above is a very brief sketch, contains much detail, and terminates 
with remarks on the paleeozoic fossils common to America and 
Europe, and on their distribution. 
In a memoir on the mineral and chemical composition of the rocks 
of the Vosges, M. Achille Delesse remarks on the passage of the dif- 
ferent igneous rocks into each other. M. Delesse observes that many 
minerals, even those widely spread and formmg important portions 
of rocks, are but little known, and he points out the felspar family, 
though it forms fifty per cent. of the crust of the globe, as being one, 
the species of which are little understood. Their chemical properties 
are nearly identical, and their composition has reference to a common 
law ; they all contam the same radical bases, in such proportion that 
the quantities of oxygen are as 1 to 3, and the different felspars are 
only saturations of these radical bases with silica. Hence the diffi- 
culty of determining the different felspars, though they belong to an 
easily distinguished natural family. 
After taking a brief view of the formation of the stratified, M. De- 
lesse proceeds to examine that of the unstratified rocks, and their 
igneous origin, glancing at the original fluidity of the earth, its con- 
sequences, and the metamorphism of rocks. Proceeding to the clas- 
sification of the non-stratified rocks, he pomts out that too much im- 
portance has been assigned to their physical characters, and too little 
value given to their chemical composition, and that it is highly de- 
sirable researches in chemical mineralogy should accompany the geo- 
logical study of the non-stratified rocks. He adds, that these re- 
searches in chemical mineralogy should be carried on with the rocks 
in place, masmuch as the chemical geologist will not otherwise be 
enabled to observe all that is required. In this manner M. Delesse 
studied the non-stratified rocks of the Vosges, carefully separating 
the isolated minerals from the main mass and subsequently experi- 
menting upon them, and as carefully also examining the main mass 
or base of the rocks. The crystals in the Belfahy porphyry were 
found to be a variety of labradorite. Augite is another mmeral found 
in this porphyry, one of those termed also Melaphyre. Its base or 
paste contained water chemically combined, as im the crystals of fel- 
spar, and M. Delesse refers to the views of M. Scheerer on this sub- 
ject. In chemical composition this paste contained silica in the same 
proportion as in the isolated crystals of labradorite, and in all the 
varieties less alumina, soda and potash, and more iron, manganese 
and magnesia, with sometimes more and sometimes less water and 
lime. The spilite of Fauconey, a vesicular rock, was found upon ana- 
lysis to be nearly of the same composition as the base of the Belfahy 
PORPDYTY 9 | 17 oxeely 
In conclusion, M. Delesse points to the approximation which these 
researches on the Vosges melaphyres establishes between them and 
basalts. The base of the two rocks is the same, being labradorite, 
and they likewise contain augite and oxidulated iron m common; 
both also contain water. The differences consist chiefly in the greater 
