30 IOWA ACADEMY OF SCIENCE 



III. Limestone from the Madeira Islands. 



The Madeira Islands lie northwest of Africa and about three 

 hundred and sixty miles from the coast. The group belongs to 

 Portugal. The soil is very fertile, and the tropical and sub- 

 tropical vegetation is very luxuriant. The specimen is a lime- 

 stone, as the analysis by Henry F. Carlton shows. 



Per cent 



Si0 2 1.17 



FeA 0.61 



CaCO s 94.11 



MgCO, 4.21 



100.10 



This specimen represents the paving material used at Funchal, 

 the chief city of the Islands. Automobiles are now invading the 

 locality but the former rapid transit was the toboggan used in 

 the streets for descending the hills and mountains, and the primi- 

 tive ox cart. The paving from this rock wears to a smooth, hard 

 metallic-like surface which facilitates the traffic. 



IV. Igneous rock from Madeira. 



This is a brownish appearing rock which easily disintegrates 

 and crumbles to a fine powder. It seems to be the origin of the 

 fertile soil of the islands. The analysis was made by Miss Nela 

 Smart. 



Per cent 



SiO„ 43.96 



Fe.O, 15.02 



A1A 12.44 



CaCO, 15.49 . 



MgCO, 9.05 



TiO, 2.02 



Na,0 0.68 



K 2 0.15 



H.O 1.05 



99.86 



This group of islands is of volcanic origin. 



Department op Chemistry, 

 Cornell College. 



