262 The Edinburgh New Philosophical Journal. 



localities. Lastly, by an examination of the nummulite limestone 

 of Cahira, and of the pyramids of Gyzeh, specimens of which he brought 

 with him from Egypt, the author has discovered that they contain 

 the microscopic animalcules of the chalk of northern and southern 

 Europe. 



" It appears that the following conclusions may be deduced in 

 reference to the whole subject. 



" 1. Many, probably all the chalk rocks of Europe, are the 'product of 

 microscopic, spiral, coralbxie animalcules, which, for the most part, 

 are quite invisible to the naked eye, some provided with calcareous, 

 and others with siliceous shells, and which are from l-24th to l-288th of 

 a line in size. 



"2. The chalk rocks of Southern and Northern Europe contain, among 

 their component parts, many perfectly similar calcareous animals, of 

 which the most remarkable are, Textularia glohdosa, Textularia aciculata, 

 and Rotalia globulosa. Rotalia ornata, Glabigerina bulloides (D'Orbigny), 

 Planulina turgida and sicula, Rosalina globidaris, Textularia aspera, brevis, 

 dilatata, and italica, together with Escharella scutellaris (Eschara scutellaris, 

 Soldani), are the remaining characteristic forms of the chalk, to which 

 are also to be added some of the species mentioned by D'Orbigny, 

 and Pusch, and the Spendina of Lord Northampton. 



"3. The cretaceous districts bordering the Mediterranean in Sicily, 

 Barbary, and Greece, and generally regarded as tertiary deposits, are 

 therefore, judging from their organisms, to be considered as chalk or 

 secondary rocks ; and the nummulite limestone of Egypt is to be 

 viewed in the same light 



" 4. The chalk strata of southern Europe, round the basin of the 

 Mediterranean, are distinguished from those of the north and east of 

 Europe by their better preserved chalk animalcules, and by the smaller 

 number of their elliptical grains ; and the converse holds good. 



" 5. The chalk strata of the south of Europe contain few or no 

 flints. Those of the north present many extremely regular horizontal 

 beds, which are often only from one to six feet separated from one 

 another. This feature was previously well known ; but, what seems 

 new and remarkable, is the observation made by the author, that in 

 the chalk strata of northern Europe, hitherto no marls of infusory 

 animals have been found like those which alternate with the chalk in 

 such prodigious abundance in Sicily, Oran, and Greece. A comparison 

 of the southern infusory-marls, and of the northern beds of flint, at 

 once presents itself to the mind. Thus, by means of this changed 

 relation, the formation of flint would receive its full explanation. A 

 greater age, as deduced from the conversion of the infusory marl-beds 



