Show arth r. r Professor ProfEsor Joseph Jeseph Le Couta Conte rec recently read a Lef Lefo o tho the Geological Society So So- cf Gf America from which we learn that hat there lire are two primary nod HUll permanent perma perm a- a neat nent Lin Linda Linds s cf f f movements of the earths earth's crust crust namely namely those which cause cluse continental con con- tinen tal surfaces and oceanic basins mid those which by interior or contraction J 3 mountains of folded ture turO Theco two are determined th the theOne theOne One lle by radial contraction the theother theother other by unequal concentric contraction that that is contraction of the interior more than the exterior There arc aro also two wo secondary kinds cf of movement which modify the effects of the other two wo and confuse oar our understanding of them hem ThesE Thet e are arp first oscillatory movements movements movements move move- ments affecting large areas and aud atio m mOvements or grav read- read Ly erosion and ion tion In the minds cf of some writers oscillatory oscillatory os- os movements have masked and obscured the effects of continent and ocean basin making and has concealed the effects and prevented the proper interpretation cf of all the others It t is believed that to make secure progress progress ress we wo must keep these several kinds of cf movements distinct in our minds San Francisco Chronicle |