Page:Popular Science Monthly Volume 88.djvu/842

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��Popular Science Monthly

���making cement. The re- maining rock is also lime- stone, but as it is not of the proper consistency for mak- ing the best cement, it was left intact.

When rock is bowed or arched up in this manner, the result is termed an anticline. This anticline is exposed at several points along the Chesapeake and Ohio Canal, Maryland.

��When the Appalachian Mountains were lifted above sea-level, millions of years ago, these strata of limestone were arched up like a bubble in pie-crust. The core of the rock has been partly mined out to make cement

��Rock Folded Like Cardboard

THE rocks in this photo- graph which are seen to be bent over in the shape of a loop were at one time — some millions of years ago — the flat bed of the ocean. When the Appalachian Mountains were uplifted above the sea they were raised with the rest of the land, and as the uplift was irregular these strata of lime- stone rocks were bowed up like a bubble of a pie-crust, which is lifted by the gas generated in the cooking of the pie. The core of this rock has been mined out for

��The House That Tin Cans Built

YOU have heard of the house that Jack built and you may have read about the house that junk built, but did you ever hear about the house that tin cans built? Huts built from tin cans — five gallon gasoline cans — are not at all un- common in that section of America between the Rio Grande and the Tierra Del Fuego, as in the locality the five gallon can is a generally accepted standard of liquid measurement. While not en- tirely suited for a dwelling in Mexico, because it is not bul- let-proof, this tin can house is very comfortable.

���There is no such word as "can*t" for the man who

built this house; but he uses can frequently, his house

being made of five-gallon gasoline cans

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