SCIENTIFIC SUMMARY. 
397 
fera, which had been deposited in the brackish-water shales of the locality 
referred to above. The foramenifera of these deposits constitute a special 
fauna, and are by no means of secondary origin, that is to say, elevated 
from marine beds, and then re-deposited by means of secondary currents of 
water. Although less abundant (specifically?) and striking than their 
kindred of the salt-water fofmations, they are nevertheless remarkable for 
the number of individuals presented. The same genera, and nearly the 
same species, which compose the true marine fauna, are found in the beds 
in question, but they are reduced to their minimum size, although the 
characteristic genera ( Nonionina , Polystomclla , Rosalina ), belong to fami- 
lies the structure of whose shell is most complex. On the whole, this 
fauna is analogous in many respects with that of the Nullipore-marls. It 
is parallel with that of the Molluscan fauna of the same origin, and hence 
it may elucidate the nature of certain deposits in which the latter should 
be present, but owing to peculiar circumstances is absent. — Vide I? Institute 
No. 1,565. 
How Granite was formed,— In delivering one of the lectures of the 
Swiney course at the Royal School of Mines, Dr. Percy objected to the 
assertion of geologists, that granitic rocks must have been formed by 
plutonic agencies, for, said he, there are certain difficulties which have 
always been in the way of accepting this view of the subject — difficulties, 
known at all events to those who have been accustomed to make experi- 
ments on the fusion of mineral substances at high temperatures. This is 
especially seen by examining the condition of quartz in granite ; it is 
always found in the crystalline condition, and has invariably a specific 
gravity of 2*6. There is not a single instance known to the contrary. 
Hence there is reason to believe that the quartz could never have been 
fused, for the moment silica is fused, no matter in what condition it w*as 
previously, a peculiar glass-like colloidal mass is produced, having a 
specific gravity which never exceeds 2*3. Therefore there is good reason 
to conclude that granite could never have been found under the condition 
of a high temperature. 
Help to the Identification of Fossil Bivalve Shells.— Under this title we 
find an article in the February number of the Geologist , but we really are at 
a loss to see in what way the writer (Mr. H. Seely) has done anything to 
lessen the difficulties which the student encounters. He proposes the 
adoption of a series of formulae as he terms them. These are really hiero- 
glypics significant of the relations of the teeth, cartilage pits, sinuses, &c. 
We do not think it likely that his scheme will be approved of, and must 
refer the reader for further information to the contribution itself. 
Geological Views of Local Savans.— It is much to be regretted that local 
scientific societies do not exercise sufficient precaution in regard to the 
previous examination of papers read before their members. A lamentable 
instance of what pseudo-scientific study may reduce a certain class of 
mind to* was exhibited at a late meeting of the Manchester Geological 
Society. A Mr. Dickinson, whose geological conceptions appear to rival 
even those of the celebrated Mr. Scattergood in regard to the laws of 
optics, communicated his opinions on the subject of “Modern and Scrip- 
tural Geology.” The learned author, after annihilating the more leading 
