Problems of American Geology; A Series of Lectures Dealing with Some of the Problems of the Canadian Shield and of the Cordilleras

by William North Rice

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1915 ... CHAPTER VII THE TERTIAKY SEDIMENTARY RECORD AND ITS PROBLEMS W. D. Matthew Nature and Source of the Tertiary Strata.--The Lacustrine Theory.--Succession and Correlation of Tertiary Formations.--The Life Record of the Cprdilleran Tertiaries. Sec. I. Nature And Source Of The Tertiary Strata Of The CORDILLERAN REGION Introduction. As the latest of the geologic periods, the Tertiary record ought to be the easiest part of the world's history to interpret and understand. The conditions were less remote from present-day conditions; the records of geologic and biologic processes and events have suffered less change, destruction, or metamorphism than those of older periods. Here in New England, indeed, the Tertiary formations have mostly been plowed up and obliterated by the great glacial invasion. But in the Cordilleran region, as far north as the Canadian border, they present wonderfully complete series of marine formations upon the coast, of terrestrial formations in the interior. The basic principle of modern geology, as enunciated by its founders, Lyell and Dana, is that the present is the key to the past, that geologic phenomena are to be interpreted through modern physiographic processes and results. To understand aright the nature and origin of the Tertiary sediments of the Cordilleras we must keep ever in mind what is going on at the present day, and especially in that region. The conditions of erosion and sedimentation in the Cordilleran region are in large part the same as those with which we are familiar in the East, but there are some conspicuous differences. I have already referred to the Glacial episode which destroyed our Tertiary records in the East as far south as New York and Pennsylvania, and covered the country with heavy banks of formations acc...

160 pages, Paperback

Published February 8, 2012