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slate clay and shale, Espichel limestone, red sandstone, hippurite 
limestone, a lower tertiary conglomerate, the Almada beds, and the 
upper tertiary sand. In the Memoirs of the Royal Academy of 
Sciences of Lisbon, for 1831, Baron Eschwege had examined a 
geological section taken across the mouth of the Tagus, and passing 
from the granite of the Serra of Cintra, to that of the Serra of Arra- 
bida. But his identifications of the Portuguese beds do not agree: 
with those of Mr. Sharpe, and have indeed the air of proceeding on 
the arbitrary assumption of a correspondence between this and 
other parts of Europe. Thus Baron Eschwege has referred both 
the San Pedro and the Espichel limestones to the magnesian 
limestone; the red sandstone formation he considers as Bunter 
Sandstein, while Mr. Sharpe refers it to the age of our Oolites: the 
hippurite limestone (now acknowledged to be the equivalent of our 
chalk and greensand) M. Eschwege makes tv be Jura limestone ; and 
the Almada beds he would have to be Plastic Clay and Calcaire 
Grossier. Mr. Sharpe is very properly attempting, bya further 
study of the organic fossils which he has procured, to confirm or 
correct the identifications to which he has been led. It is only by 
thus starting from different points, and tracing strata by their conti- 
nuity, that we can hope to cover the map of Europe, and finally 
the world, with geological symbols cf a meaning fully understood. 
PALHONTOLOGY. 
The portion of our subject which we term Paleontology, might 
at first sight seem to form a part of zoology rather than of geology ; 
since it is concerned about the forms and anatomy of animals, and 
differs from the usual studies of the zoologist only in seeking its 
materials in the strata of the earth’s crust instead of upon its sur- 
face. Yet a moment's thought shows us how essential a part of 
our science the zoology of extinct animals is; for in order to learn 
the history of the revolutions which the earth has undergone, we 
must seek for general laws of succession in the remains of organic 
life which it presents, as well as in the position and structure 
of its brute masses. And since such general laws must necessarily 
be expressed in terms of zoology, it becomes our business to define 
those terms, so that they shall be capable of expressing truths which 
