When Hitler continued his aggression, Chamberlain pledged Britain to defend Poland's independence if the latter were attacked, an alliance that brought Britain into war when Germany attacked Poland in 1939.
FIND OUT MORE. The Earth is covered in a layer of solid rock called the crust. Rocks are either SEDIMENTARY, IGNEOUS, or METAMORPHIC. Almost all rocks made of minerals, but different rocks contain different mixtures of minerals.Granite, for example, consists of quartz, feldspar, and mica.IND OUT MORE. The Earth is covered in a layer of solid rock called the crust. Rocks are either SEDIMENTARY, IGNEOUS, or METAMORPHIC. Almost all rocks made of minerals, but different rocks contain different mixtures of minerals.
The crust is the thinnest of the Earthâs three layers and the top part of the lithosphere. It is only about 8 kilometers (5 miles) thick under the oceans and 32 kilometers (20 miles) beneath continents.The rocks in the crust are primarily made of oxygen, silicon, aluminum and iron.ore About the Mantle. The crust is an important part of the lithosphere, but below it lies the other component: the top part of the upper mantle. This is denser than the crust. Like the crust, it contains rocks with large amounts of silicon and oxygen, but the mantle also has significant amounts of iron and magnesium.