198 



NUMMULITES. 



minute ; they are often piled on each other almost as 



closely as the grains in a heap, of corn ; and they occupy 



an important place among fossil shells, because of their 



prodigious numbers in certain circumstances. Closely 



piled together, they form a 



considerable portion of the 



entire bulk of many extensive 



mountains. They abound in 



the Alps and the Pyrenees, 



and some of the pyramids 



and the sphinx of Egypt are Nummuiite. 



composed of limestone loaded with these remains. 



Minute examination, indeed, discloses occasionally 

 vast masses of microscopic shells, that surprise us as 

 much by their minuteness as their abundance. The 

 mode in which they are sometimes crowded together 

 may be gathered from the fact, that Soldani collected 

 from less than an ounce and a half of stone found in 

 the hills of Casciana, in Tuscany, 10,454 microscopic 

 chambered shells. Of several species of these, four or 

 five hundred weigh but a single grain ; of one species he 

 calculates that a thousand individuals would scarcely 

 weio-h so much. He further states that immense numbers* 



o 



of them passed through a paper in which holes had 

 been pricked with a needle of the smallest size. 



