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WHAT IS BATHYBIUS? 659 
already known that many deep-sea localities existed, in which 
the Globigerina-mud did not occur; and it had even been 
suggested that its range was limited to that of the warm 
Gulf-stream. Dr. Carpenter confirms this general conclu- 
- sion, and points out that its prevalence is connected with a 
bottom temperature of 45°, which in our northern latitudes 
can only be attributed to the Gulf-stream. 
Bathybius yet requires to be considered in two other 
important relationships — the one geological and the other 
zoological. 
Chalk, examined microscopically, has long been known to 
abound in minute ovate organisms, known as crystalloids, 
associated with the Globigerinæ and Textillariæ, of which 
chalk mainly consists. I recognized the organic Fig. 102. 
origin of these bodies in 1847, and figured (Fig. 
102) one of them very imperfectly, viewed as an 
opaque object, in my memoir "On some of the Mi- 
croscopie Objects found in the Mud of Levant ;"* 
but, ignorant of Coccoliths, I concluded that 
they belonged to some minute form of Oolina or Lagena. 
More recently Mr. Sorby has subjected these bodies to a 
much more careful examination, and both he and Dr. Wal- 
lich have identified them with Professor Huxley's Coccoliths. 
It now appears that both Coccoliths, Cyatholiths and Cocco- 
spheres, occur fossilized in the chalk, establishing, in a 
remarkable manner, the close resemblance of the conditions 
under which the chalk-beds were formed and those existing 
along the traet of the Gulf-stream at the present day. Dr. 
Carpenter goes even further than this, and regards it as 
"highly probably that the deposit of Globigerina-mud has 
been going on over some part or other of the North Atlantic 
sea-bed, from the Cretaceous epoch to the present time (as 
there is much reason to think that it did elsewhere in 
anterior geological periods), this mud being not merely a 
chalk formation, but a continuation of the chalk formation ; 





* “ Trans. Phil. Soċ., Manchester,” Vol. viii, fig. 71. 
