114 
POPULAR SCIENCE REVIEW. 
strata have recently attracted considerably the attention of geologists, and 
hence the following resume of M. Hebert’s conclusions wUl be of interest to 
our readers ; — (1) The clay of the plateaux in Picardy may be the most 
ancient of the quaternary series ; but if so, it must be different from the 
Limon*Hesbayen, of Dumont, which Lyell has identified with the Loess, and 
must also differ from the clays worked at St. Acheul, above the red gravel. 
(2) The red gravel deserves more attention than it has yet received, and, hi 
M. Hebert’s opinion, should not be connected with the Loess of the Khine, 
as has been done by M. D’Archiac, Its uniform presence over a rich tract 
renders it important as a landmark, and as proving the greater antiquity of 
underlying diluvial beds. (3) The gravel of Moulin-Quignon may be consi- 
dered to be derived from debris washed down the slope of the hill, and to be 
a mixture of roUed flmts, with red gravel, whose date is not determined. 
From this it follows that the Moulin-Quignon beds are newer than the red 
gravel. (4) The Loess of Picardy, which overlies the grey gravel, is older 
than both the red gravel and Paris Loess. (5) The Loess is not to be 
regarded as the mud of glaciers once covering Europe. In some iustances 
the red gravel covers and penetrates the loess and upper beds of grey gravel, 
.filling large and irregular swaUow-holes, and affecting the upper beds of the 
Calcaire Grossier,” at a height of 55 metres (180 feet 5 inches) above the 
sea, in exactly the same maimer as it affects the grey gravel. He thinks that 
these results may fairly be attributed to the action of the sea and marine 
currents, and alludes to the terraces and parallel roads of Picardy as being 
analogous to those of Glen Eoy, and others in Great Britain. (6) The age 
of the flint-bearing clay is still doubtful, it is probably more ancient than 
the plastic clays of Picardy. This view is supported by the fact that, in the 
Forest of Dreux there are found beds of plastic clay overlying this “ flmt- 
bearing clay,” an intermediate bed of white and yellow sand being also 
observable. — See G-eological Magazine, No. III. 
New Fossil Fish from the Lower Chalk . — Dr. Gunther describes a new 
fossil fish, which has lately been added to the British Museum collection. 
It is from the lower chalk of Folkestone, and appears to be the type of a dis- 
tinct genus. It is twenty inches long, with the vertebral colunm and the 
fins tolerably well preserved, whilst the head, unfortunately, has suffered so 
much that scarcely any portion of it can be distinguished. It is proposed to 
term the new genus Plinthojphorus or tile-bearing, from the nature of the 
peculiar osseous scales which are observed upon the lateral portions of its 
body. Writing of these scutse. Dr. Gunther observes, “ Their general form 
is arrow-head-shaped, with a longitudinal keel running from one end to the 
other ; the uncovered, broader posterior part is corrugated ; the anterior 
portion, which is covered by the preceding scutee, is more slender, tapering, 
and smooth. All these scutes were so connected that they could easily 
slide one above the other, allowing the lateral motions, and the temporary 
extension of the body after feeding, or during the season of propagation ; and 
the whole arrangement reminds us of a similar chain of scutes in Doras and 
Hypostomus.’^ 
The Homologies of Eurypterus have been very clearly indicated by Mr. H. 
Woodward, in a paper in which he reviews the researches of other palaeonto- 
logists. Mr. Woodward points out some serious errors into which Professor 
