UNIVERSITY OF TORONTO 



ART 





' and Str 



uctural 



ILLUSTRATIONS. 



FIG. PAGE. 



1. Map showing mean annual rainfall of the United States 2 



2. Pollution of pond by stock 1 1 



3. Pollution of stream from outhouses 1 1 



4. Spring from bedded-limestone 15 



5. Subterranean stream in limestone 15 



6. Spring of gravity type fed from unconfined waters in porous sands 14 



7. Fissure spring (artesian type) 18 



8. Pollution of ground water by sewage discharging into sink 19 



9. Dairy spring from polluted underground stream 19 



10. Spring receiving pollution from stock and surface wash 23 



11. Spring receiving wash from fertilized land 23 



12. Polluted spring in center of city street 25 



13. Diagram showing manner in which springs may be polluted by subsurface 



drainage 26 



14. Relation of areas of outcrop to dip 31 



15. Section illustrating conditions governing movement of ground water away 



from streams or lakes 32 



16. Diagram showing relation between depth and permanence of wells 41 



17. Diagram showing action of clays or shales in confining water in sand or sand- 



stone 41 



18. Relative size and storage capacity of dug and drilled wells 42 



19. Arrangement of grains in sands and sandstones 42 



20. Grains in sand and sandstones with intervening pores filled with mineral 



matter 43 



21. Difference in conditions of adjacent wells in limestone 43 



22. Wells in jointed rocks 44 



23. Diagram showing possibility of pollution in till 45 



24. Limestone passage connected with sinks 46 



25. Section showing relation of water table to surface irregularities 51 



26. Map showing position of water table and lines of motion of ground water .... 52 



27. Section of an artesian basin 54 



28. Section showing transition from pervious to impervious bed 54 



29. Section illustrating artesian conditions in jointed crystalline rocks 55 



30. Section illustrating cbnditions of flow from solution passages in limestone. ... 55 



31. Section illustrating conditions of flow from vesicular trap 57 



32. Artesian system showing progressively higher outcrop of deeper beds 58 



33. Artesian system showing progressively lower outcrop of deeper beds 58 



34. Open dug well and wooden bucket 79 



35. Bored well, showing wooden curb and valve bucket 79 



36. Drive point and well augers 91 



ix 



