264 FIRST FORMS OF VEGETATION. 
in the primeval world long before man was ushered 
upon the scene, and they are at the present day 
employed in altering and modifying the grand 
features of the globe ; in producing results which 
man is as incapable to predict as he is powerless to 
prevent. Who is there that can gaze upon these 
wonderful plants, which thus, as it were, connect 
the ages and the zones, without a dizzy sense of 
the infinity and permanence of nature, and the 
power of Him whose judgments are unsearchable, 
and whose ways are past finding out? 
majority of species now living in our waters, and forming deposits 
which will become rock at some future time ; and as some species 
are peculiar to lakes and rivers, and others to seas and firths, while 
some affect deep and others shallow water, these tiny plants are 
capable of furnishing considerable information to the geologist, 
with regard to the conditions under which raised sea-beaches and 
fresh-water limestone rocks were originally deposited, and the cir- 
cumstances which operated in the production of the different strata 
in which they occur. I may add, as an illustration of the universal 
diffusion of these plants, the curious fact, that the late Dr. Gregory 
found numerous most interesting diatomaceous forms in small frag- 
ments of soil not exceeding a pinch of snuff, adhering to specimens 
of exotic plants in herbaria. In every case, without exception, he 
found these organisms ; and in all, the proportion to the whole 
non-calcareous earthy residue was wonderfully large. The soils in 
which the most numerous species were found, were respectively ob- 
tained from the Sandwich Islands and Lebanon. Many of Ehren- 
berg’s profound observations were made on portions of foreign soil 
procured in this manner, and his example should stimulate collec- 
tors of plants to preserve carefully every vestige of earth adhering 
to the roots of their exotic specimens, as in this way many new 
forms may be brought to light, and many rare ones studied in the 
quiet and leisure of home, without the trouble and fatigue of col- 
lecting them in their native localities. 
