OF SEVERAL PARTS OF WESTERN ASIA. 357 



ens ; but I doubt not, that the rock at these locahties forms part of 

 the same series which was observed by Ehrenberg ' at Hamam Fa- 

 raun and Tor, in the Sinaian portion of Arabia,' ' constituting hilly 

 masses in Upper Egypt,' and ' continued eastward far into the inte- 

 rior of the Great Desert plain, trending eastward toward Palestine.' 

 Damascus is a point further to the north and east than Ehrenberg 

 mentions. How interesting the thought, that the Mount of Olives, 

 and probably the Holy Sepulchre itself, was formed by these mi- 

 nute creatures, of which more than a million exist in every cubic 

 inch of the rock ! ' 



" Having determined the presence of these creatures in the speci- 

 mens, I next endeavored to ascertain if they would afford any evi- 

 dence as to the geological age of the formation from which they 

 were taken. Ehrenberg had already referred the specimens exam- 

 ined by him to the epoch of the chalk, relying for the correctness of 

 this statement on the identity of the predominating forms with those 

 found in the chalk of Europe. With the forms of the English chalk, 

 recent examinations have made me somewhat familiar ; and I feel 

 no hesitation in saying, that the specimens sent by you contain 

 forms specifically identical ; and to this statement I can add, that 

 the predominant forms of the chalk marls from the vast regions of 

 the Upper Missouri and Mississippi are also the same. As the 

 prevailing Polythalamian forms of the tertiary epoch are mvcli 

 larger and of distinct species, need we hesitate to refer the Asiatic 

 and American deposits to the cretaceous group ? That the refer- 

 ence is correct in regard to the American deposits, you will remem- 

 ber was shown by the character of the organic remains of other 

 classes of animals found by Mr. Nicollet. 



" To enable you to judge of the close resemblance of the forms of 

 PolyLhalamia, I have made, with the camera lucida, a series of com- 

 parative sketches. (PI. XHI.) They are very imperfect, for, as the 

 little shells are often considerably hidden by adhering calcareous 

 particles, I found some difficulty in taking the outlines. Ehrenberg 

 mentions Tcxtularia glohulosa and Rotalia glohidosa, as among the 

 chief constituents of chalk. Figs. 2 and 3, I drew from the most 

 common forms, in a specimen of English chalk. I have little doubt, 

 that fig. 3 is the Textidaria globulosa, and I strongly suspect that 

 fig. 1 is Rotalia glohulosa. I, however, do not profess to be acquainted 

 with the genera and species of the Polythalaraia ; but, whatever 

 the names of figs. 2 and 3 may be, there can be no doubt of their 



