72 
Professor Agassiz has clearly pointed out that the black slate of 
Engi in the canton of Glaris in Switzerland, so celebrated for fossil 
fishes, is of the lower cretaceous age. This shows the great value of 
Paleontology ; for nothimg can be more unlike, than a piece of Glaris 
slate to white chalk. I possess a good series of these fish, through 
the kindness of Lord Enniskillen. 
In the east of Europe, near Dresden, the chalk assumes a dark grey 
colour, but is readily recognised by the appearance of Ammonites, Sca- 
phites, teeth of fish, &c. In Poland the white chalk reposes on the 
greensand, as in this country. In the south of Russia, Sir R. I. 
Murchison has declared the chalk undistinguishable from that of 
England. 
M. Dubois, in his late researches, has pointed out that many parts 
of the Circassian mountains are cretaceous, and their appearance similar 
to our English downs, with their slopes covered with trees. We trace 
the Chalk period through the Crimea into Asia Minor, where, accord- 
ing to Mr. Hamilton, the beds become semi-crystalline, and are fre- 
quently hollowed out into basins filled with tertiary deposits. 
The Morea and intermediate islands contain cretaceous fossils. 
The island of Rhodes, and part of Syria on the Lebanon range imme- 
diately above Beyroot, are composed of chalk containing flints, but few 
fossils. In the neighbourhood of Lisbon, Mr. Sharp has found the 
Hippurite, in hills traceable many miles to the south of the Tagus. 
In North America there are four distinct forms in which the Chalk 
period is recognized: Ist, in a thin mass almost entirely composed of 
comminuted corals ; 2nd, in a compact limestone of a yellowish colour ; 
3rd, in a subcrystalline limestone ; and 4th, by a white limestone, the 
whole series being loaded with cretaceous fossils, and extending in an 
irregular crescent near three thousand miles. 
In South America, according to M. d’Orbigny, the Cretaceous period 
is largely developed, and can be traced from Columbia to Tierra del 
