1896.] Geology and Paleontology. 131 



Keith 1 " gives very brief descriptions of the granites, quartz porphyries, 

 andesites and the Oatoctin schist of the region. The last named rock 

 is apparently a sheared basic volcanic. All the rocks present evidence 

 of having suffered pressure metamorphism. 



GEOLOGY AND PALEONTOLOGY. 



Notes on the Fossil Mammalia of Europe.— I, Comparison 



of the American and Eikopkan forms of Hyracothkrhm.— 



Historically speaking llyracotherium is one of the oldest of known 

 fossil Perissodactyla. and it is of importance phylogenetically to com- 

 pare the representatives of this genus in En rope with those of America, 

 in order to acquire an exact knowledge as to the evolution of the molar 

 cusps of the New and Old World species. My attention was called to 

 this subject on account of having studied Euprotogonia of the Puerco, 

 a genus which as well known, is considered to have one of the most 

 primitive types of Ungulate molars. 



The importance of having accurate drawings of the teeth of fossil 

 mammals is nowhere better illustrated than in Hyraeotheriuvi. In the 

 case of the enlarged drawing of the teeth 1 of H. (=Pliolopkwi) r«ipi- 

 ceps which has been copied extensively in works on vertebrate paleonto- 

 logy, we obtain quite an erroneous idea of the exact form of the 

 molar cusps. 



Kowalevsky 2 in his great work on " Aitthnu-otherium *' tigu res some 

 of the molars of the type of Hyracotherium namely : H. leporinum. and 

 I should judge from his description that he had studied Owen's type in 

 London. However, his criticism of Owen's drawing of the type of 

 Hyracotherium is very accurate, and as Kowalevsky remarks, Owen's 

 figures gives one the idea that the teeth of the type are strictly buno- 

 dont, whereas they are really transitional in structure between a real 

 bunodont type, such as Eupr«togonia and a truly lophodont form like 

 Systemodon. 



» 14th Ann. Rep. U. S. Geol. Survey, p. 285. 



