412 PROF. EHRENBERG ON FOSSIL INFUSORIA. 
always immediately surrounds the nodules. This Steinmark of Kaschau 
exhibits however, under the microscope, a great resemblance to the 
Gaillonella distans, as it appears in the Saugschiefer of Bilin. I have, 
from the remarkable character of the primary formation, repeatedly 
examined and compared these and similar phenomena, and prefer to 
declare them openly than to keep them secret. I shall however continue 
my observations with close examination, and publish the results if they 
lead to any discovery, when they are sufficiently matured. 
The more probable appears the proverb, partly old and partly new, 
Omnis calz e vermibus, Omnis silex e vermibus, Omne ferrum e vermi- 
bus, the more necessary it is, by continual and close examination, which 
cannot be the work of a day, to separate facts from opinions, and not 
to envelope them in mystery, but by careful observation to confine them 
within the probable and attainable limits which nature has assigned. 
We may regard as hitherto ascertained facts that 
1. Bergmehl 
2. Kieselguhr 
a Polipsmbiefar 30. fs.ikisey maabasagwte «de 
A, SAGE SQNICLET | .ckicicigi'se> une senermsen tom Tertiary formations 
_ 5. The semi-opal of the Polirschiefer.. 
consist entirely or partly of the shells of shield-infusoria. 
The following species of stone are very probably of the same nature : 
6. The semi-opal of the Dolerit......... 
7. The (precious) opal of the eae 
8. The flint of the chalk ,. 
9. The Gelberde (yellow Paes Wialeet Madang 
10. The Raseneisenstein ......... 
11. Certain kinds of Lee ae 
\ Newest formation 
Secondary and primary 
formations. 
* The examination of a boulder from the Mark (Brandenburg) which has 
been regarded as Schwimmstein (compare Kléden, Geognost. Mem. 1834, 
p- 30.) has lately proved to me that its chief mass consists of just the same 
detached siliceous spindles of sponges and of the minute globules (infusoria 
Pywidicula’?) which the flint boulders of the Mark inclose in great numbers. 
These bodies also lie in the meally covering of the flint. This Schwimmstein 
therefore bears the same relation to the flint as the Polirschiefer to the semi- 
opal, and it belongs to the chalk. 
