MEMORANDA. 305 



sion is warranted, that doubly refractive silica has no existence 

 in the organic world. — J. VV. Bailey, Ibid. 



On some Specimens of Deep Sea Bottom, from the Sea of Kanit- 

 schatka, collected by liieut. Brooke, U. S. N. — The following is a 



copy of a letter from Professor Bailey to Lieut. Maury, of the 

 National Observatory, Washington, D. C, dated West Point, 

 New York, January 29th, 1856. 



I have examined with much pleasure the highly interesting 

 specimens collected by Lieut. Brooke, of the U. S. Navy, 

 which you kindly sent me for microscopic analysis, and I will 

 now briefly report to you the results of general interest which 

 I have obtained, leaving the enumeration of the organic con- 

 tents and the description of the new species for a more detailed 

 account which I hope soon to publish. 



The specimens examined by me were as follows : 



No. 1. Sea bottom 2700 fathoms, lat. 56° 46' N., long. 168° 

 18 E., brought up by Lieut. Brooke with Brooke's lead. 



No. 2. Sea bottom 1700 fathoms, lat. 60° 15' N., long. 

 170° 53' E., brought up as above, July 26th, 1855. 



No. 3. Sea bottom 900 fathoms, temperature (deep sea) 

 32 Saxton, lat. 60° 80' N., long. 175° E. 



A careful study of the above specimens gave the following 

 results. 



1st. All the specimens contain some mineral matter, which 

 diminishes in proportion as the depth increases, and which 

 consists of minute angular particles of quartz, hornblende, 

 feldspar, and mica, 



2nd. In the deepest soundings (No. 1. and No. 2.) there is 

 least mineral matter, the organic contents (which are the same 

 in all) predominating, while the reverse is true of No. 3. 



3rd. All the specimens are very rich in the siliceous shells 

 of the DiatomacerE, which are in an admirable state of preserv- 

 ation, — frequently with the valves united and even retaining 

 the remains of the soft parts. 



4th. Among the Diatoms, the most conspicuous are the 

 large and beautiful discs of several species of Coscinodisciis. 

 There is also (besides many others) a large number of a new 

 species of Rhizosolenia, a new Syndendrium.) a curious species 

 of Chcctoceros with furcate horns, and a beautiful species of 

 Asteromphalus, with from five to thirteen rays, which I pro- 

 pose to call Asteromplialus Brookei, in honour of Lieut. Brooke, 

 to whose ingenious device for obtaining deep soundings, and 

 to whose industry and zeal in using it, we are indebted for 

 these and many other treasures of the deep. 



5th. The specimens contain a considerable number of the 

 siliceous spicules of sponges, and of the beautiful siliceous 



