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ANNALS NEW YORK ACADEMY OF SCIENCES 
lseozoic and Wealdian fishes), and Dr. M. Leriche, Maitre de Confer¬ 
ences of the University of Lille (upper Cretaceous and Tertiary 
fishes). The complete list of them will be published later. 
2. Amphibia. Fossil amphibia are at present known only from a single 
level, the Wealden of Bernissart. 
3. Reptilia. Fossil reptilia are found at nineteen distinct levels, well 
correlated stratigraphicallv. I have personal charge of their study. 
The principal levels will be considered later in detail. 
4. Birds. Fossil birds are known from four distinct levels. 
5. Mammals. Fossil mammals are found at twelve different geological 
levels. The description of the cetaceans is intrusted to Prof. O. Abel, 
University of Vienna. 
C, Fossil Reptiles of the Jurassic of Belgium. 
1. Ichthyosaurus communis Conybeare, 1822. 
Lower Lias, suburbs of Arlon, in Belgian Luxembourg. 
2. Ichthyosaurus platyodon Conybeare, 1822. 
Middle Lias, Stoekem, near Arlon, in Belgian Luxembourg. 
3. Plesiosaurus homalospondylus Owen, 1869. 
Middle Lias, Dampicourt, near Virton, Belgian Luxembourg. 
4. Steneosaurus bollensis Jaeger, 1828. 
Upper Lias, Halanzy, near Messancy, Belgian Luxembourg. 
N. B. I have not yet published anything upon these reptiles. 
Their occurrence may be tabulated as follows: 
Lias. 
Lower 
Middle 
Upper 
1. Ichthyosaurus communis. 
1. Ichthyosaurus platyodon. 
1. Ichthyosaurus sp. 
2. Plesiosaurus homalo- 
2. Plesiosaurus sp. 
spondylus. 
3. Steneosaurus bollensis. 
D. The Reptiles and Batrachians of the Wealden of Belgium. 
Horizon. The Wealden is the fresh-water facies of the Neocomian, which 
forms the base of the Cretaceous. 
