10 SANTA BARBARA SOCIETY OF NATURAL HISTORY. 



Ehrenbergh has described about one hundred species, from 

 the infusorial stratum of Richmond, Virginia. This bed is 

 thirty feet thick. There is a bed in Bohemia fourteen feet 

 thick, of fresh water tertiary. 



According to Dana, there is a bed at Monterey; California, 

 over fifty feet thick, which is, no doubt, a continuation of our 

 bed, which probably extends along this coast as far north 

 and south as the tertiary extends. 



The diatomacese were probably the pioneer life of the globe, 

 representing both the animal and vegetable life that was to 

 come. In the rocks older than the tertiary, the beds have 

 mostly disappeared, their structure and chemical nature 

 favoring their combination with other material to form various 

 silicates, flints and conglomerates. Though silica in its com- 

 mon state is insoluble, and in its combinations forms the 

 most durable rocks, yet the silica secreted by diatoms is 

 readily dissolved in alkaline solutions, and in that state con- 

 verts bones, wood or other organic material into solid rock. 

 Beds of sand, gravel and inorganic material of all kinds, in a 

 loose condition, are changed to compact, durable stone. Half 

 way up the Santa Ynez range is an old oyster bed two feet 

 thick, with the shells and mud in which they lived, so firmly 

 cemented that it is almost impossible to break or separate 

 them. This process of rock making is still going on, as can 

 be readily seen on the hillside. Solutions of silica from the 

 higher beds have penetrated the lower, and changed them to 

 a hard flinty diatomite, and, mixing with the gravel and 

 boulders of the drift, have made a solid conglomerate. 



In this way, these minute infusoria have been busy for 

 ages, world building, and they are still busy. 



They are not confined to warm latitudes, like the coral 

 polyp, but, in the extreme north, in the Sea of Kamtchatka, 

 they are as abundant as rhizopods in the Atlantic. 



Diatoms figure largely in the material of dust storms that 

 prevail in southern Europe. Ehrenbergh found thirty-nine 

 species in the dust, from one shower, that fell at Lyons, 

 October 17th, 1846. From one which fell in Italy in 1803, he 



