154 
PROF. T. EUPERT JONES-ORIGIN AND 
Coccoliths, etc. —Mr. Sorby found, some years ago, that certain 
specimens of Chalk consisted almost wholly of Globigevince (90 per 
cent.); other parts of the Chalk have fewer of these, but more 
Textularice , or other forms ; and in some cases Inoceramus prisms or 
Pentacrinite ossicles, etc., form most of the mass. In all cases, 
however, the fine granules are present, which in some cases seem to 
be amorphous particles, or inorganic (as indeed they all were thought 
to be by Ansted and early observers), but they mostly prove to be 
minute organic bodies of definite shape and size, now known as 
Coccoliths. Whether or no any chemical precipitates, of a cal¬ 
careous nature, have given origin to some of the particles, has not 
yet been decided. 
These minute organic bodies (the largest less than —oVoth of an 
inch in diameter) are oval (rarely circular) double discs, like a shirt- 
stud. Sorby, Huxley, Wallich, Carter, Schmidt, and others have 
studied them; and Dr. Wallich has compared the separate views, 
and repeated his own, so that by referring to his paper * * * § much can 
be seen at once. He regards these little Coccoliths as being 
peculiar calcareous symmetrical bodies set in on the outside of the 
small sarcodic bodies (coccospheres) which he discovered floating 
in the ocean, and having sometimes the shapes of some Eorami- 
nifera, such as Textularia , etc. Huxley regarded the Coccoliths 
as individual distinct organisms, and Carter referred to them as 
sporangial bodies of some Algce such as Melobesia. Huxley and 
Schmidt lay stress on the granular zone or ring occurring some¬ 
times between the two discs; and indeed Schmidt regards it as 
very important and equivalent to the ring on the base of certain 
Rhabdoliths common in the Chalk of some places. These also are 
minute and shapely bodies, found in sea-muds with the Coccoliths.f 
They are club-shaped, but varied, and have been found, attached by 
their broad bases to a small spherical body, floating in the sea (rhab- 
dosphere, Wyville Thomson). Some regard them as being probably 
of vegetable alliance. Recurring to the granular rings of the 
Coccoliths, we find that such little organisms were observed in the 
Chalk years ago by Ehrenberg, and figured in his magnificent 
* Mikrogeologie,’ and that they were seen also long since by the 
Rev. J. B. Reade in the English Chalk. J In those days they were 
quite misunderstood, and there still remains much to be known 
about them.§ 
Flint. —Whether calcareous or siliceous originally, the particles, 
fragments, and complete organisms, large and small, composing the 
Chalk, are in many instances found to be more or less changed into, 
or to be imbedded in the flint which is so abundant as nodules and 
bands in some strata of the Chalk. There are some permanent 
* ‘ Ann. and Mag. Nat. Hist.,’ ser. 4, vol. xix, p. 342, etc. 
f lb., ser. 4, vol. x, p. 359, etc. 
X See Mantell’s ‘ Wonders of Geology,’ 7th ed. 1858, vol. ii, p. 953, fig. 213. 
§ Some very important observations on Coccoliths (with figures) have been 
given by Dr. W. J. Sollas in the * Geological Magazine,’ Dec. 2, vol. iii, 1876, 
pp. 540-542, pi. 21. 
