110 Von Rtchthofen on the Nummulitic formation in China. 



cent and local origin ? Have these brine insects acquired their 

 singular tastes within a recent geological period (say the Quater- 

 nary), having lived at first as do their allied species, in foul 

 fresh water, or amid decaying matter in damp localities? Be- 

 fore these and other questions can be answered, we must have 

 analyses of the waters, and a review of the European literature 

 of the subject,* and larger collections of brine animals from our 

 own country. 

 Peabody Academy of Scieuce, Salem, Nov. 16, 1870. 



Art. Xyni. — On the existence of the Nummulitic formation i:. 

 China ; by Baron von Richthofen. (From a letter to Prof. 

 J. D. Whitney, dated Su-Chan, China, Dec. 12th, 1868). 



The subject of this letter is the discovery of the occurrence oj 

 the Nummulitic formation in China, a fact w^hich adds one more 

 to the short series of formations known, chiefly by the lahorsof 

 Mr. Pumpelly, to enter into the composition of this country. 



Mr. Pumpelly cites, on the strength of a statement by Re?. 

 Mr. Edkins, the island of Si-Tung-ting in Tai-hu lake (a sheet 

 of water of about eight hundred square miles, sixty miles west 



was naturally led tt 



Devonian limestone. Inquiries which I made in Shanghai con 

 firmed the fact of the occurrence of fossils. There, too, the] 

 were considered as Devonian, and I was advised by a reall.^ 

 skillful geologist, to study their mode of occurrence, as thi 

 would give me the clue for the structure of most portions o 

 * I am indebted to Mr. F. Walker of London for the following note on the habit 

 ?L*^ ^""f'^^ 'P''^'"" "^ ^^^^y'i'-^ ^°d its allies. He writes under date of Pec 

 ■ 3 of Ephydra -<: 



