244 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



Charpentier had previously included Dactylopores amongst 

 the Foraminifera, and the name of Foraminiferal limestone 

 rapidly began to be applied to the Alpine deposits in 

 question. Meunier-Chalmas, however, showed in 1877 that 

 the so-called Dactylopores were not Foraminifera and did not 

 belong to the animal kingdom at all, but were Calcareous Algae. 

 In view of Giimbel's results, these algal organisms, under 

 the new name of Gyroporella, were raised to a place of the 

 first importance in the history of Alpine rock-building, since 

 their aggregated remains form a very great portion of the 

 enormous thickness of limestone and dolomite which adorn 

 the Eastern Alps. 



In his work on Chemical Geology, Bischof had expressed 

 his opinion that the thick deposits of marine limestone occur- 

 ring in the geological formations had been formed by pelagic 

 faunas which derived the calcareous substance from the calcium 

 carbonate in sea-water. Volger in 1857 showed that the 

 source of the lime was for the most part not the very small 

 proportion of lime carbonate dissolved in sea-water, but the 

 gypsum or lime sulphate. Recent researches support Volger's 

 results, and enter in more detail into the chemical processes 

 by which the animal tissues are enabled t,o assimilate the lime 

 as a carbonate, and to throw off the sulphur in chemical com- 

 binations with waste products, more especially ammonia. 



The "tests" or "casings" of pelagic Foraminifera are some- 

 times calcareous, sometimes arenaceous, and are sometimes 

 imperforate (e.g. Miliolina, Orbitolites), sometimes provided 

 with a number of small apertures or foramina (e.g. Nodosaria, 

 Globigerina, Rotalia). 



D'Orbigny in 1825 examined both recent and fossil speci- 

 mens of Foraminifera, and misled by the elaborate appearance 

 of the shells, he placed them in affinity with the Nautiloid 

 group of Molluscs, but since then the microscopic study of Fora- 

 minifera and the extended means of comparison with related 

 forms of lowly animal life have shown this group to belong to 

 the Protozoa (Subd. Reticularia, Carp.); from geological, geo- 

 graphical, and zoological sides of research, abundant evidence 

 has been given of the pre-eminence of testaceous material in 

 pelagic deposits. 



As early as 1839, Ehrenberg proved that chalk rocks were 

 composed of fossil Foraminifera, and demonstrated a similar 

 aggregation of minute calcareous shells belonging to recent 



