MICROSCOPICAL EXAMINATION 



To Prof. A. D. Bache. 



Superintendent of Coast Surve-y. 



West Point, March 8, 1848. 



Dear sir: 



1 propose in this communica „ion to give you a more complete report of the 

 results of my examination of the soundings which you kindly supplied me with, 

 than I was able to do when I sent you a notice of my first hurried observations. 



The specimens were each subjected to the following modes of examination; 



1st. Inspection when dry with a pocket Stanhope lens. 



2d. About a cubic inch of each specimen was placed in a watch glass with 

 water, and agitated to bring the Polythalamia to the surface ; the larger organic 

 forms could then be easily picked up on the point of a needle and examined 

 separately. 



3d. Portions of the soundings were diffused in water on a glass slide, and 

 when dried were coated with Canada balsam, and examined as transparent 

 objects. 



4th. By levigation the Hghtest particles were floated off", spread out on glass, 

 and then coated with Canada balsam ; by this means the infusorial remains 

 were most easily detected. 



By the above means the specimens yielded the results given below: 



FIRST LINE OF SOUNDINGS. 



Specimens from line E, about S. E. from Montauk Point. 



E, No. 73, 13 fathoms ; lat. 40° 59' 35"; long. 71° 55' 40". 



This specimen is quartzose sand with black specks. Nothing of interest was 

 observed in it, and in consequence of its being mingled with grease the infusorial 

 forms, if present, could not be detected. 



E, No. 37, 19 fathoms ; lat. 40° 59' 55"; long. 71° 48' 55". 



This is a coarse gravel, mingled with ash colored mud. By levigation it 

 yielded a considerable number of silicious shells of Infusoria, among which were 

 Gallionella sulcata, Coscinodiscus lineatus, C. excentricus, C. radiatus, Actinop- 

 tychus senarius, Actinocyclus quindenarius, Rhaphoneis rhombus, Triceratium 

 alternans, Bailey ; Graramatophora oceanica, Dictyocha speculum, Dictyopyxis 

 cruciata ; with spiculse of Sponges or Alcyonia, small bivalve crustaceans, and 

 a few small Polythalamia, chiefly species of Rotalina. 



