THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[THIRD SERIES.] 

 No. 45. SEPTEMBER 1861. 



XIX. — On the Organic Ongin of the so-called ' Crystalloids' of 

 the Chalk. By H. C. Sorby, F.R.S. &c. 



The appearance of Dr. Wallich's interesting paper, published in 

 this Magazine (vol. viii. p. 52), in which he alludes to my having 

 found in chalk objects similar to Coccoliths, induces me to give 

 an account of ray researches on the subject. I do not claim the 

 discovery of such bodies in the Chalk, but to have been the first 

 to point out that they are not the result of crj'stalline action, 

 that they are identical with the objects described as Coccoliths 

 by Prof. Huxley*, and that these are not single separate indivi- 

 duals, but portions of larger cells. 



So far as I am aware, the illustrious Ehrenberg was the 

 first who pointed out the ovoid bodies occurring in chalk, in a 

 paper read at the Berlin Academy, Aug. 18, 1836, on "New 

 Microscopic Characters of earthy and compact Minerals t-" 

 After alluding to the various minute bodies constituting some 

 kinds of kaohn and agaric-mineral, he says that the most re- 

 markable of all are those found in chalk, which shows small, 

 flat, eUiptical disks, similar to each other, consisting of only a 

 few concentric rings, usually only one, and an internal nucleus 

 of irregular character, as shown in his figure, pi. i. 2 b, in Pogg. 

 Ann. He again alludes to them in his Memoir on Chalk and 

 Chalk-marl J, saying that in a former j)aper he had declared 

 that the preponderating substance of chalk, which foniis the 

 cementing material, was minute, elliptical, flat, granular bodies 

 and their fragments. He looked upon them then, as he still 

 continued to do, as concretions of a crystalline character, whose 



• Deep-Sea Soundings in the North Atlantic Ocean, made in H.M.S. 

 Cyclops. London, 1858. 



t Monatsberichte, 1836; PoggendorflTs Annalen, 1836, sxxix. 101. 

 + .\bhandluugen der k. Akad. der Wissen. zu Berlin, 1838, 6/. 



Ann. ^- Mag. N. Hist. Ser. 3. Vol. viii. 13 



