652 GEOLOGY. 



and of the coordinating faculties even at that early stage, and a study 

 of the relations of these to their fellow creatures opens up the first known 

 chapter in the sociological record of the earth's inhabitants. From 

 this stage onward the progress in the development of the higher facul- 

 ties, and of the sociological relations of the leading forms, is one of the 

 most instructive phases of the great history. Such a study reveals the 

 fact that many questions, narrowly supposed to be purely human, have 

 had their prototypes in the earlier experiences of the animal kingdom. 

 Some of these questions have found solutions, temporary or permanent, 

 which passed under the test of ages to whose length human experience 

 affords no parallel, and have received the sanction or disapproval of 

 such tests according as they were well or ill adapted to the actual con- 

 ditions involved. If one seeks the lessons of hist-^ry in the largest sense, 

 he cannot wisely neglect the prolonged record of the great biological 

 family. 



II. SPECIAL CONTRIBUTIONS OF THE ORGANIC KINGDOMS. 



An essential part of the historical chapters of the second volume 

 will consist of the description and illustration of the life progress of 

 the successive periods. It will suffice here to give a preliminary synopsis 

 of the kinds of record made by the several groups of plants and animals. 



A. Contributions of the Plant Kingdom.^ 

 The record of plants in the early geological ages is extremely imper- 

 fect. In the very earliest times the conditions seem to have been wholly 

 Unsuited to the preservation of any relics of life; but even after animal 

 remains were abundantly preserved in the sea sediments, the plant 

 record was still very meager for a long period. This was probably due 

 in the main to two chief causes: (1) the probable softness and perisha- 

 bility of the early types of vegetation, and (2) the fact that vegetation 

 is preponderantly terrestrial. At no time has marine vegetation reached 

 a high development. Land conditions favor decomposition, transpor- 

 tation, and erosion, and through these, destruction; and only under 

 rather occasional and exceptional conditions did the old lands leave a 



^Reference works: Scott, Studies in Fossil Plants, 1900; Zeiller, Elements de 

 Paleobotanique, 1900; Potonie, Lehrbuch der Pflanzenpaleontologio, 1899; Seward, 

 Fossil Plants, 1898; Solms-Laubach, Fossil Botany, 1887. 



