LIST OF ILLUSTRATIONS 



ric. FACE 



1. Geological hammer, compass-case, and belt ... 33 



2. Clinometer ......... 35 



3. Maps showing the effect of incorrect topography in <1 



ing geological lines ....... 38 



4. Some useful signs in geological surveying . . . -41 



5. Weathered crust, showing concentric zones of oxidation . 56 

 5<i. Granite weathering along its joints, top of Ifc-n:... 



Aberdeenshire ........ 57 



6. Dolerite (basalt) weathering spheroidal!}. North yueensferry 58 



7. A piece of granite. Crystalline structure .... 60 



8. Piece of porphyritic and cellular lava (showing crystals and 



steam holes) ........ 62 



9. Piece of conglomerate, showing the tic rounded 



water-worn aspect of the component parts of many frag- 

 mental rocks ........ 64 



10. Piece of volcanic tuff ....... 65 



11. Piece of coal, composed of matted stems of Sigillan*: 



Lfpidodendron. Carmarthenshire (De la Heche) . . 66 



12. Outlines of mountains formed of stratified or sedimentary 



rocks. Rocky Mountains. (Hoyden's Kfport of Survey 



of Western Territories, 1874) 72 



13. Outlines of a mountain formed of crystalline rock. Rocky 



Mountains (Haydtn's Re fort for 1874) .... 74 



14. Common Cockle (Cardium edule) 78 



15. Fossils standing in relief on a weathered surface of limestone 81 



1 6. Ripple marks in sandstone ...... 83 



17. Rain-prints on sandstone 84 



1 8. Sun-cracked surface of red sandstone marked with foot- 



prints, Hildburghausen, Saxony 85 



