THE 



GEOLOGICAL MAGAZINE 



VOLUME LIX. 



No. XII.— DECEMBER, 1922. 



ORIGINAL ARTICLES. 



Notes on the Tertiary of Southern Lower California 



(Mexico). 



By Aknold Heim, Zurich. 

 (PLATES XXI AND XXII.) 

 Introductiox. 

 "PvURING spring and summer of 1915, an expedition was sent to 

 -^ the peninsula of Lower California (Baja California) by a Swiss 

 Colonization Company. The scientific work was under the direction 

 of the writer, who enjoyed excellent assistance from his friends 

 Prof. Dr. Ad. Hartmann, of Aarau, and Top. Eng. E. Kluth, of 

 Zurich. Although little time was available for stratigraphic 

 studies, some of our observations of that almost unknown country 

 seem to be worthy of publication. 



In fact, some 10,000 square miles, hitherto regarded as Cretaceous, 

 have been found to consist of Tertiary formations, subdivided 

 by several unconformities, and covered by volcanoes and lava 

 fields. 



Originally, a large volume with maps, sections, and photographs 

 was planned, containing Geography, Biology, and Geology. This 

 plan was frustrated by several misfortunes. 



The whole collection of rock samples, which was addressed and 

 despatched for presentation to the Mineralogical Museimi of the 

 University of Zurich, after having been held up at New York, 

 was thrown away by the American Express Co., in September, 1918, 

 according to an investigation made by the Minister for Switzerland, 

 at Washington, D.C. None of these rocks, especially those of the 

 crystalline series of Magdalena and Cape Kange, have yet been 

 described. 



The collection of Tertiary fossils was transmitted in 1915 to 

 Dr. Ralph Arnold, of Los Angeles, Cal., who kindly agreed to make 

 a close study of them, and to publish his paleontological results 

 in a joint paper with the author. Unfortunately, his war work 

 prevented him from undertaking this study. He therefore 

 transmitted the fossils to Professor Dr. Bruce L. Clark, of California 

 University. The first determinations, by Ralph Arnold and B. L. 

 Clark, were published in the Bulletin of the Geological Society of 



VOL. LIS. — NO. xn. 34 



