IN THE MUD OF THE LEVANT. 83 



matter for combination with animal organisms. 

 The fact has been already noticed by Ehrenberg.* 



The hard Chalk of the North of Ireland also 

 abounds in Polythalamia, though they cannot be 

 separated from the consolidated matrix ; but when 

 splinters- are broken off, the contour of the shells 

 is marked by translucent lines in the opaque 

 stone, showing that they once existed there as 

 abundantly as in the English Chalk. The con- 

 solidation of the stratum from contact with erupted 

 rocks, has obviously altered the appearance of 

 the minute fragments, which, in the friable Chalk 

 rocks of Cambridge, look almost like amorphous 

 lime, but which, in the Irish stratum, can no 

 longer be identified as organic atoms ; — an 

 interesting example, conducting us to the more 

 solid limestones from whence nearly all traces of 

 microscopic organisms have disappeared. 



The latter appears to be the case with part of 

 the Chalk strata of the Lebanon range. Though 

 in some of these Ehrenberg found Foraminifera, 

 I could not detect any traces of them in the 

 cream-coloured limestones of the Gebel Suneen 



* I'hil. Mag. Lon. and Ediu. Vol. xviii. \). 397. 



