Geological Society : — Anniversary of 1839. 227 



which they are well exhibited. His series (exclusive of igneous 

 rocks) consists of San Pedro limestone (which rests upon the 

 granite,) slate clay and shale, Espichel limestone, red sandstone, 

 hippurite limestone, and 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 Ta- 

 gus, and passing from the granite of the Serra of Cintra, to that 

 of the Serra of Arrabida. But his identifications of the Portu- 

 guese beds do not agree with those of Mr. Sharp, and have in- 

 deed the air of proceeding on the arbitrary assumption of a cor- 

 respondence between this and other parts of Europe. Thus 

 Baron Eschwege has referred both the San Pedro and the Espi- 

 chel limestones to the magnesian limestone ; the red sandstone 

 formation he considers as Bunter Sandstein, while Mr. Sharps 

 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 to be the Jura limestone ; and the Almada 

 beds he would have to be Plastic Clay and Calcaire Grossier. 

 Mr. Sharpe is very properly attempting, by a 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 of a meaning fully under- 

 stood. 



PALJEONTOLOGY. 



The portion of our subject which we term Palssontology, 

 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 diflJers from the usual studies of the zoologist only 

 in seeking its materials in the strata of the earth's crust instead 

 of upon its surface. Yet a moment's thought shows us how es- 

 sential 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 succes- 

 sion 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, 



