16 CONTENTS. 



Chapter XXIV. Postglacial development of connecting rivers of the Great Lakes — Continued. 

 St. Clair River — Continued. 



St. Clair delta — Continued. Page. 



Age of the delta - 482 



Gravel spit at head of St. Clair River 483 



Lake St. Clair 484 



Detroit River 485 



Detroit River at Detroit 485 



Distributaries 485 



Lake Rouge 486 



Detroit River near Trenton and Amherstburg 487 



Distributaries near Trenton 488 



Early distributaries 488 



Creases 489 



Late distributaries 489 



Grosse Isle natural canals 490 



Rockwood distributaries 491 



Distributaries near Amherstburg 491 



Relation of early distributaries to Lake Rouge 492 



Development of the Detroit River estuary 492 



Drowning of Lake Erie shore - 492 



Drowned distributary channels 494 



Recent and progressing changes in Detroit River 494 



Flooding of tributaries 496 



Cause of flooding 496 



Tributaries of Detroit River 497 



Tributaries of Lake St. Clair , 497 



Tributaries of St. Clair River 498 



Progress of overdeepening and drowning or flooding ~ 498 



First deepening 498 



Channel making during time of Lake Algonquin 499 



Second or last deepening 499 



Present drowning or flooding •. . 500 



Relative ages of the connecting rivers , 501 



Chapter XXV. Deformation of shore lines, by F. B. Taylor 502 



Possible causes 502 



Hinge lines and areas of uplift 502 



Ice attraction _ 506 



Resilience following depression by ice weight .■ 506 



Relations of uplift to retreat of ice 506 



Theoretical principles 508 



Theoretical and actual uplift 509 



Lake Superior region 509 



Ice lobes and driftless reentrants 510 



Relation of ice weight and hinge lines to ice margin 511 



Effect of driftless areas 511 



Shifting of the hinge line 514 



Absence of recent faults 515 



Pre- Wisconsin depression and resilience • ■ 515 



Relation of isobases to the pre-Cambrian boundary 515 



Eustatic and oscillatory movements 516 



Tectonic earth movements 516 



Wide range of phenomena , . 516 



Crustal creep 517 



Conclusions 518 



Chapter XXVI. Economic resources, by Frank Leverett 519 



Erratics in the drift 519 



Marl or bog lime ■ 519 



Peat 520 



Clay 520 



Sand and gravel 521 



Underground waters 522 



Soils 522 



Index 525 



