32 GEOLOGICAL MEMOIRS. 



On the Occurrence of the Nummulitic Formation in Japan and the 

 Philippines. By Ferdinand von Rjchthofen. 



[Ueber das Yorkommen von Nummulitenformation auf Japan und den Philip- 

 pinen ; von Ferdinand Freiherr von Richthofen. Zeitschrift der Deutschen 

 geologischen Gesellschaft. Band xiv. Heft 2. Februar— April 1862, p. 357.] 



The Nummulitic formation has hitherto been kno^n to extend east- 

 wards only so far as British India, and southwards scarcely so far as 

 the Tropic of Cancer. In Java it has not been fonnd ; for it appears 

 that in this island the Orbitolites, which occnr very abundantly in 

 Trachyte-tuff, have been mistaken for Nummulites. The mining 

 engineers of the Dutch East Indies mention the presence of Nummu- 

 litic rocks in the southern part of Borneo, where they are said to 

 contain coal. It is possible, however, that these beds are a repeti- 

 tion of the Orbitolite-containing strata of Java. The author was 

 therefore all the more interested in finding, in September 1860, 

 evidence of the Nummulitic formation in Eastern Japan, and conse- 

 quently about fifty degrees further eastward than it was known 

 before to occur. In May 1861 he also discovered the formation in 

 Luzon, near the fourteenth degree of north latitude. 



In the stone -polishing establishments at Yokohama, near Yeddo, 

 the author purchased small boxes and pebbles, consisting of a blackish 

 marly limestone, containing abundance of Nummulites ; he was in- 

 formed that the stone was obtained from a mountain lying eastward 

 from Yeddo, — probably in the Principalities of Simosa and Kadsusa, 

 and that it occurred in very large masses. These few pieces are 

 sufficient to prove the occurrence in Japan of the Nummulitic forma- 

 tion ; and of it they are at present the only evidence. 



In Luzon, on the contrary, the Nummulitic formation appears to be 

 very widely distributed, and is an important element in the consti- 

 tution of the island. The author then describes the distribution of 

 the limestone in the neighbourhood of the well-known limestone- 

 quarry near Manila, called the Caeva de San Matteo ; he remarks 

 that fossils have often been searched for in this limestone, but that, 

 as none had been found, it was supposed to be at least of Jurassic 

 age ; he was so fortunate, however, as to search in a quarry where 

 Nummulites occurred in it in abundance, together with a few obscure 

 Oysters. The Nummulites are of various sizes, and belong to several 

 species. 



Herr von Richthofen also found the same Eocene formation on 

 the south coast of the Island of Mindarao, where it possesses, how- 

 ever a more varied lithological character — consisting of limestone, 

 sandstone with Plant-remains, shale, and marl. He concludes by 

 remarking on the improbability of the Nummulitic Limestone of 

 Nippon and Luzon being isolated patches, and infers that the limits 

 of the old Nummulitic sea must be extended from the Himalaya 

 Mountains through China to Japan, and also so as to include the 

 remaining Philippine Islands. [H. M. J.] 



