In the study of paleontology, one of two main objects may be the end to be attained: First, where the fossils are studied as assemblages of organic forms characteristic of certain beds and formations and from them is gathered the key to unravel stratigraphy and build up the historical record of the rocks. This important aspect of paleontology is perhaps the leading line of paleontologie work at the present time, at least among students of invertebrate fossils. Without decrying this work in the slightest, it must be remembered that stratigraphy is an application of paleontology and is not the whole subject. Its bearing is somewhat comparable to the study of geographical distribution to the student of recent forms of animals and plants.
The second object of paleontologie study is where fossils are studied from the point of view of the structure, development, and systematic affinities of the fossils themselves. This . . .