91 



Experiments with heat outlined for Eighth Grade can be used heiv,, 

 and results used in connection with wind, ocean currents, evaporation 

 and condensation, and disintegration of rock. 



2. Formation of Earth's Crust. 



(a) "'Cooling and contraction. 



(b) Formation of igneous rock. 



(c) Formation of water. Hydrogen, oxygen. 



(1) Condensation and evaporation. 



(2) Formation of rain, lakes, rivers, ocean. 



(3) Review oxygen and hydrogen. 



3. Igneous Rocks. 



(a) Review lava granite, contorted gneiss. 



(b) Compare crystalline structure of rocks. 



To show that igneous rocks are due to the action of heat, form crys- 

 tals of different substances. Make a saturated solution of alum, salt, 

 sugar or copper sulphate; pour part of the solution into a saucer, and 

 part over a woolen string suspended in a bottle. Allow the solution 

 in the saucer to cool rapidly and that in the bottle to cool slowly. 

 Observe form and size of crystals. Compare crystals of quartz, cal- 

 cite, copper pyrites, iron pyrites, etc. Account for difference in size 

 of crystals. Compare size and shape of snow crystals on cold and 

 mild days. 



IV. North America. 



1. Archaean Rock. 



(a) Granite, gneiss, syenite, hornblendic, quartzite. 



(b) Deposits of iron ore. 



2. Distribution of Archaean Rock. 



(a) North northeastern Canada, Adirondacks and Lake Superior 



region. 



(b) East north of New England to Georgia. 



(c) West along ranges of mountains which later became Cor- 



dilleras. 



(d) Land areas surrounded by ocean. 



V. Erosion. 



1. Cause Chemical and Mechanical Forces at work on exposed Ig- 



neous Rock. 



2. Effect Sedimentary Rock. 



(a) Origin of sedimentary rock igneous rock. 



(b) Position upon igneous rock. 



(c) Location around igneous rock. 



Review subject of erosion outlined for Sixth Grade. 



