30 OUR COMMON BRITISH FOSSILS. 



Scotland. This is a tolerably large kind, being nearly 

 one-eighth of an inch in length. 



The Carboniferous limestone in many places is 

 very rich in foraminifera. According to Mr. Etheridge, 

 these are represented by fourteen genera and forty- 

 eight species. The most important genera are — 

 Saccamina^ Stacheia, Nodosinella^ Dentalina^ Textii- 

 laria^ Fusiilhia^ Calculina^ etc, 



The White Chalk, however, is tfhe great storehouse 

 of well-preserved and easily extracted fossil foramini- 

 fera. These minute shells are especially abundant in 

 some kinds of "flint-meal," obtainable from hollow 

 flints, as already described. The chief genera of 

 Cretaceous foraminifera are — Globigerina, Dentalina^ 

 Marginidina, Frondicularia^ Textiilaria, Gandiyina, 

 Verneuilhia, Bidiminay Truncatidinay Rosalina^ Ro ta- 

 lma, Cristellaria, Lituola, etc. 



These minute but exceedingly beautiful fossils may 

 be extracted from any piece of white chalk as follows: — 



First, get together an apparatus consisting of two 

 ordinary medicine bottles, and about eighteen inches 

 of small indiarubber tubing, such as can be purchased 

 at any chemist's. Procure a piece of soft chalk, the 

 softer the better, and that which has been partially 

 broken up by the action of the weather better still. 

 Scrape this with a knife to a fine powder, and put 

 it in one of the bottles, which should not be more 

 than about one-tenth full ; then fill up the bottle 

 three-parts full of water and shake vigorously and 



