310 Mr. F. Chapman on 
In reference to the supposed zeolitic crystals in the tests of 
the Rhetic Foraminifera, it may be presumed that they may 
have been formed in tranquil water and subsequently washed 
by tidal or other action within reach of the numerous 
Foraminifera, which utilized them in the construction of their 
tests. 
Remarks on the Rhatic Foraminifera as compared with those 
from other Geological Horizons. 
So far as I am aware no records have been published of 
Foraminifera having been found in strata of undoubted 
Rheetic age. They are not unknown in the older (Triassic) 
beds, notably from the Muschelkalk of Thuringia*; and 
the younger strata of Liassic age contain Foraminifera in 
abundance. 
In his paper on “ The Range im Time of Foraminifera” TF 
Professor T’. Rupert Jones gives a table of genera, in which 
fifteen spaces are filled up in the Rhetic column. These 
genera are again recorded in the ‘Catalogue of the Fossil 
Foraminifera of the British Museum’ f. In the earlier of 
these works, however, Professor Rupert Jones has remarked §: 
“Nubecularia [the remark applying also to the other genera 
mentioned] is Rheetic in origin (taking the blue clay of Chel- 
laston as of that age).” The Foraminifera of the clay 
supposed to have come from Chellaston were originally 
described as of Triassic age ||; they have, however, since 
been determined by Professor Rupert Jones to be neither of 
Triassic nor even Rhetic age, as was formerly supposed, but 
to have a true Liassic facies, and probably from Leicestershire. 
A comparative study of the Rhzetie Microzoa shows that they 
bear some close resemblances to the fatina obtained from 
Upper Paleozoic strata. Several of the species of Ammo- 
discus found at Wedmore were already known from Permian 
and Carboniferous rocks, whilst many forms belonging to 
the genus Stacheia were previously known only from Carbon- 
iferous and Silurian §] strata. 
* L. G. Bornemann, “ Beitrige zur Kenntniss des Muschelkalks, 
insbesondere der Schichtenfolge und der Gesteine des Unteren Muschel- 
kalks in Thiiringen,” Jahrb. k. preuss. geol. Landesanst. Berlin, 1885. 
+ Proc. Geol. Assoc. vol. ii. (1872) p. 175. 
{ 1882, pp. xiv & xv. 
§ Op. supra cit. p. 178. 
|| Jones and Parker, ‘On some Fossil Foraminifera from Chellaston, 
near Derby,” Quart. Journ. Geol. Soc. vol. xvi. (1860) p. 452. 
| The Silurian specimens under the name of Psammosiphon, Vine. 
