William S. Cooper

Vegetational Development Upon Alluvial Fans in The Vicinity of Palo Alto, California

Introduction The study here presented had its origin in a distributional and causal investigation of the superb forest of oak which characterizes the environs of Palo Alto, California. The construction of a detailed map proved necessary, in the course of which it became evident that the native vegetation over much of the area had been seriously modified by cultural operations. A thorough search of the literature, and the personal testimony of old residents of the district, combined with field observations, made it possible to reconstruct the original vegetation of the region in a satisfactory manner. It soon appeared that the oak forest is a late stage in a successional sequence of great interest, and the dynamic phases of the problem thereupon assumed the place of first importance. Moreover, certain features came to light which were difficult to reconcile with current systems of ecological thought. The excuse for this rather minutely detailed local study, if such be needed, lies in its possible helpfulness toward the solution of some of the more general problems of ecology. The field work was done in the years I9I3-I9I5 and the data obtained have been subjected to study at intervals since then. Mr. G. F. Beardsley, of Carmel, California, has been of the greatest assistance in the task of reconstructing the original vegetation of the region. He resided here before the plant population had been seriously disturbed, and has drawn upon his remarkably accurate memory to good effect. I gratefully acknowledge my indebtedness to his cooperation. I wish also to offer my sincere thanks to Mr. W. 0. Clark, formerly of the U. S. Geological Survey, now of Honolulu, Hawaiian Islands, who allowed me, with the approval of the Geological Survey, to use voluminous data of his collecting relating to depth of water table in the region. [Ecology, Vol. VI, No. 4 (pp. 325-473) was issued October IO, 1925.]

Reconstruction of a Late‐Pleistocene Biotic Community in Minneapolis, Minn.

Our knowledge of the postglacial migrations of the flora and fauna of eastern America is still fragmentary and uncertain. It is based largely on inference from the present ranges and successional interrelations of species, direct fossil evidence being thus far extremely meager. Every find of postglacial remains should therefore be utilized to the uttermost, as we have endeavored to do in the present case. In the spring of I923, during excavation for the new building of the Northwestern National Life Insurance Company, on Fifteenth Street opposite Loring Park in Minneapolis, abundant and well-preserved remains of plant and animal life of late Pleistocene age were discovered. A careful study of the locality and the deposits and an extensive collection of the organic materials have yielded the facts and conclusions presented in this paper.