500 
TOPULAR SCIENCE REVIEW. 
thickness of horizontal beds of sandstone, which are unaltered at their contact 
with the syenite. This sandstone formed the great mining district of the 
Egyptians in Sinai, and is now worked for turquoises , which appear to occur 
more or less in veins. Raised beaches were discovered by the author on the 
western side of the peninsula, at elevations of from twenty to thirty feet. 
The Belgian Bone Caves. — Quite recently a paper was presented on these 
caverns to the Cotteswold Naturalists’ Field Club. It was, we believe, the 
product of the joint labours of the Rev. W. S. Symonds and Sir W. Y. 
Guise, and treated of the Caves of Furfooz, near Dinant. The authors ex- 
pressed the opinion that the geological period of the entombment of the 
human jaw, with the remains of the extinct animals with which it was asso- 
ciated, may be assigned to the epoch known to geologists as the loiv level drift 
period of Prestwich, a period recent in a geological sense, but enormously 
remote when measured by time , for the cold of the Glacial epoch was not alto- 
gether passed, and the extinct mammalia were still in existence. It was the 
period of the deposition of the old river drifts of Menchecourt, near Abbe- 
ville, which contain their human flint implements, interbedded with the bones 
of the mammoth and rhinoceros ; the period of the deposition of the ancient 
river beds near Salisbury, and other parts of England, which teach the same 
history, and also, they believe, of the English bone caverns. It happens, how- 
ever, that a good deal of the materials of Mr. Symonds’ paper were obtained 
from M. Dupont, who is employed by the Belgian Government to investigate 
the caverns, and who was visited by Mr. Symonds during his tour. This, at 
least, is the assertion of a contemporary, and, if it be true, Mr. Symonds is 
much to blame. However, we have no doubt that something is to be said on 
the other side, and we trust that in our next issue we shall be able to offer- 
some contradiction to the following assertions made in a letter addressed to 
the Reader , of September 8th, and referring to Mr. Symonds’ paper on the 
Belgian Caves : — “ Taking, as I do, some interest in these caves, I cannot 
reprobate too strongly this disingenuous and underhand publication. All 
those who have visited the Belgian caves near Dinant know that M. Edouard 
Dupont is employed by the Belgian Government to make the scientific investi- 
gations into these caves. M. Dupont will, in time, publish his own report ; 
and it is a breach of good faith for any person who may have visited Dinant, 
and inspected M. Dupont’s collection, or who may have enjoyed that generous 
man’s hospitality, to publish without the knowledge of the original discoverer 
a garbled and untrue version of the facts.” 
Geological Gold Periods. — The various periods of the world’s geological 
history at which gold has made its appearance on the earth’s crust is a sub- 
ject of the highest interest and importance, and has been ably dealt with in a 
paper by Mr. David Forbes, and which has been just published. He divides 
the Gold-epochs into two, thus : — (1) The older or auriferous granite outburst ; 
(2) The younger or auriferous diorite outburst. The first occurred some time 
between the Silurian and Carboniferous periods. The gold formations belong- 
ing to this period present themselves in Australia, Bohemia, Bolivia, Brazil, 
Buenos Ayres, Chile, Cornwall, Ecuador, Hungary, Mexico, New Granada* 
Norway, Peru, Sweden, Ural, Wicklow ; and also such deposits of gold as 
are found intruded as quartz nodules and veins, as if interstratified in the 
Cambrian and Silurian systems, which he believes to have been rendered 
