different kinds c 



They show that the Italian seas in Eocene time were within the 

 limits of the coral-reef seas. 



17. Fhysikalische Krystallographie und Einleitung in die 

 krystallographische Kenutniss der wichtigeren 8uhstanzen ; von 

 P. Gkoth. 528 pp. 8vo. Leipzig, ISYB. — Professor Groth of Strass- 

 bourg has done excellent service for the science of mineralogy by 

 putting in the hands of students a clear and comprehensive work 



ubject of 

 Bd by a s 



Physical Crystallography. He takes up first the gene 

 s and the undulatory theory of lig 



•eful descriptions, aided by excellent illustra- 

 tions, makes the whole subject very intelligible without the use of 

 mathematical formulae. The fundamental laws of light are then 

 explained, and, as following from them, the various optical proper- 

 ties of crystallized minerals ; the whole being treated in a thorough 

 and comprehensive manner. The properties of crystals in their 

 relation to heat, electricity, and magnetism, are also fully described. 

 The second part of the work embraces a discussion of the forms 

 of crystals, based especially upon the general laws of symmetry 

 which characterize the different systems. The illustrations through- 

 out the work are of a high degree of excellence: this is especially 

 true of the colored plates at the end of the volume. A special 

 chapter is devoted to the description of the various instruments 

 [ in optical researches, and a considerable number of de- 



at' 



III. Zoology 



1. Recent Corals from Tilibiche, Peru, nearly SOOO feet above the 

 sea-level.— Frofessor A. Agassiz, in his recent South American tour, 

 found a coral limestone at Tilibiche, 2,900 to 3,000 feet in eleva- 

 tion, about 20 miles in a straight line from the Pacific. The ravine 

 where it occurs is about 450 feet below the general level of the 

 nitrate basin of Peru. Two species of corals, modern in aspect, 

 are described by L. F. Pouitales, both new species, Isophyllia du- 

 plicata, and Convexastrcea f Peruviana, and besides these a Mil- 

 lepore was observed near M. alcicornis. Professor Agassiz con- 

 cludes that the Pacific, within comparatively recent times, extended 

 through gaps in the Coast Range and made an internal sea, which 

 stood at a height of not less than 2,900 feet, and probably much 

 above this, as the sea must have played an important part in the 

 deposition of the salt and the nitrates of the nitrate beds ; and 

 consequently, that there has been an elevation since the formation 

 of the coral reefs, of not less than 2,900 feet. The presence of 

 other extensive saline basins at a height of 7,000 feet seem to make 

 the submergence still greater. The existence of eight species of 

 Allorchestes (Amphipod Crustaceans), a salt-water genus, m Lake 



