SCIENTIFIC SUMMARY. 
323 
Iguanodon in the Kimmeridge Clay . — Professor Prestwich announces ( Geo- 
logical Magazine, May 1879)^ a most interesting discovery which has lately 
been made at Cumnor Hurst, near Oxford. The workmen engaged in the 
brickfield there found, in digging, a quantity of hones, which they brought 
to the Museum at Oxford, and which, on being cleaned, displayed the 
characteristic peculiarities of Iguanodon . Many of the vertebrae are entire ; 
the jaw, although in fragments, contains many teeth in position ; and one of 
the feet, with the claw-joints, is almost complete. The larger bones are 
nearly all broken ; but many of them may probably be united, and. it is be- 
lieved that the skeleton was nearly complete when found. The animal is 
smaller than the Wealden Iguanodon Mantelli, and may perhaps be a young 
individual of that species, but Professor Prestwich is inclined to regard it as 
a distinct species, with smaller and more delicately formed bone3. On visit- 
ing the spot, Professor Prestwich learned that the bones had been found in a 
seam of yellow sandy clay two or three inches thick, at a depth of about 
four feet, and the clay above this seam contained perfectly characteristic 
Kimmeridge Olay shells, such as JExogyra virgula, Cardium striatulum, 
Thracia depressa, and Ammonites biplex, with Lima pectiniformis and Serpulce . 
Hence it would appear that Iguanodon, or some closely allied Dinosaur, was 
not confined to the Lower Cretaceous and Wealden periods, but existed 
also during that of the Kimmeridge Olay. 
MINERALOGY. 
The Presence of Didymiwn and Cerium in Minerals. — As Horner has 
shown the presence of these metals in different pyromorphites and scheelites 
by aid of the spectroscope, so Cossa has now recognized them in apatites, 
scheelites, osteolites, and coprolites, not only by means of the spectroscope, 
but by separating them in the form of oxalates. He has also found the 
cerium metals in marble and in bones. From a kilogramme of Carrara 
marble two centigrammes of cerium oxalate were obtained. The mus- 
chelkalk of Avellino is found to contain still larger quantities of cerium 
compounds. A kilogramme of washed bone ashes, such as is used for the 
formation of cupels, yielded three centigrammes of cerium oxalate. These 
observations go to show that the cerium metals are widely spread throughout 
nature. Oossa is at present occupied with an examination of natural 
phosphates and the ashes of plants. — (Per. cliem. Gesett. xi. 1837.) 
Artificial Formation of Nepheline and Laucite. — We some time since 
! directed attention to the method employed by F. Fouque and A. Michel 
j! Levy to form felspars artificially. By the same method they have recently 
! prepared the minerals above mentioned. Nepheline is formed when a mixture 
of silicic acid, alumina, and sodium carbonate, in such proportions that the oxy- 
gen of protoxide, sesquioxide and acid are as 1 : 3 : 4, are heated together ; 
; white silk-like crystals are obtained which under the microscope are seen to 
be small hexagonal prisms (they are 0T2 min. long, and 0-06 min. broad), 
I which accord in every respect with natural crystals of nepheline. If sorne- 
j what more silicic acid be taken, like that corresponding to the proportion 
1 : 3 : 4J, a completely crystalline mass is obtained, which bears in its optical 
t 2 
