126 APT END IX. 



APPENDIX No. 3. 



Letter from. Mr. Arthur Mead JEdtcards on the Results of an Examination, under tlia 

 Microscope, of some Japanese Infusorial Earths and other Deposits of China and 

 Mongolia. 



New York, January 14, 1866. 

 Raphael Pumpelly, Esq. 



Dear Sir: I have, agreeably to your request, made a microscopical examination of the specimens 

 of earths you submitted to me some time since, and have to report thereon as follows : — 



They were thirteen in number, and the results of examining each one separately and carefully is 

 recorded below. With regard to the two specimens numbered 6 and 9, in which J have found the 

 siliceous loricas of Diatomacese, I have to regret that the time at my disposal lately has been so short 

 that I have been unable to identify the various species detected therein, much less have I been able 

 to do as I would have wished, that is to say, transmit to you at this time a complete list with descrip- 

 tions and figures of the supposed new forms. 



No. 1. " Efflorescence from the xilains of the Eirnoor, Mongolia^ 



This specimen contains some straight sponge spiculae and broken crystalline particles of -a deep 

 olive-green color ; otherwise it consists mostly of fine particles of sand. Erom the presence of the 

 sponge-spiculse I judge this deposit to be decidedly of aquatic origin and probably marine ; although 

 the form of the spiculae, as well as I can tell from their generally broken condition, is such that they 

 may have belonged to a fresh-water species of sponge. 



No. 2. " Terrace dejMsit (loam of lower terrace) Te Hai, Mongolia." 



Under the microscope this is very similar to the above, that is to say, it contains many of the green 

 cry.stalline particles found in No. 1, but no sponge-spiculse that I have been able to detect. 



No. 3. Efflorescence (with sand), from the flat at the Te Hai Mongolia." 



This is also very like the first in appearance, in containing green crystals, but, like the second 

 specimen it contains no sponge-spiculfe, so that in neither of these two last numbers have I found any- 

 thing that would assist in determining their origin. 



No. 4. "Gobi limestone (ste2:)pe deposit in part), Nov. 28, 1864." 



Consists almost entirely of fine white particles of calcareous matter, but shows nothing to indicate 

 the circumstances or conditions under which it was deposited. This was to be expected as the micro- 

 scope rarely reveals anything peculiar in limestones, their origin being best denoted by the character 

 of the large fossils when these are present. 



No. 5. "Lake loam, Siwan, N. Chihli," is mostly sand, and contains a few of the before men- 

 tioned green crystals, but no traces of the remains of organized beings. 



No. 6. " Fo7'ming bluff near Nietanai, Yesso." 



No. 9. " From bluff near Nietanai, Yesso." 



These both evidently belong to the same deposit, taken at different depths most likely, as is evident 

 from the remains of organized forms which they contain. They are plainly from a marine tertiary 

 stratum similar in character to that discovered by Prof. Rogers underlying the cities of Richmond 

 and Petersburg in Virginia, and also like that found by Prof W. P. Blake at Monterey in California. 

 The last mentioned deposit I have at present under examination for the State survey of California, 

 and it has been found by Prof Whitney, and his coadjutors of the survey, at different points extending 

 some hundreds of miles down the Pacific coast, varying slightly in appearance, color, hardness, or 

 the grouping of the forms contained in it, as it was collected at various localities, but plainly showing 



