28 Baron A. Humboldt on Petrifactions , or 
of formation have been very remote from each other. We 
may conceive that, under the same zone, in a country of but 
little extent, generations of animals have succeeded each other, 
and have characterised, as by particular types, the periods of 
formation ; but, at great horizontal distances, beings of very dif- 
ferent forms, may, in different climates, have simultaneously 
occupied the surface of the globe, or the basin of the ocean. 
Further still, the position of /3, between * and y, proves that the 
formation of /3 is anterior to that of y, and posterior to that of 
« ; but nothing gives us the precise measure of the interval be- 
tween the epochal limits, and different isolated deposits of /3 can- 
not be simultaneous. 
There seems to result from the facts which the zeal and saga- 
city of naturalists have united within these few years, that, if 
we should not always expect to find, as Lister pretended, in 
each different formation different organic remains, yet that most 
commonly formations which are shewn to be distinct by their 
relative situation and composition, contain in the most remote 
countries of the globe associations of entirely similar species. 
M. Brongniart, whose labours, together with those of other ce- 
lebrated mineralogists, have so much advanced the study of 
subterranean conchology , has lately made known the striking 
analogies which certain formations of Europe and of North Ame- 
rica present with regard to fossil organic bodies. He has endea- 
voured to prove that a formation is sometimes so disguised, that 
it is only by its zoological characters that it can be recognised, 
(Brongniart, Hist. Nat . des Crust. Fossiles , p. 57, 62). In 
the study of formations, as in all the descriptive physical scien- 
ces, it is the assemblage of many characters which should alone 
guide us in our search after truth. The specific description of 
the remains of plants and animals contained in the different for- 
mations, presents us, so to speak, their Flora or Fauna. Now, in 
the primordial, as in the present world, the vegetation and the 
animal productions of different portions of the globe, appear to 
have been less characterised by some isolated forms of an extra- 
ordinary aspect, than by the association of many forms specifi- 
cally different, but analogous to each other, notwithstanding 
the distance of the placevS. On discovering a new land near 
Torres Straits, it would not be easy to determine, from a small 
