By 'these mountains' I assume you are referring to the Andes Mountains of South America. The desert formed in the rain shadow of the Andes is the Atacama Desert.
South American Pacific coast.
Only the Pacific coast along South America is desert. Most of the Pacific coast line in the rest of the Americas is not desert. In South America the prevalent wind direction is from the east. The Andes Mountains prevent moisture from the east from crossing, creating a rain shadow desert along the Pacific Coast. In North America the prevalent wind direction is from the west so the coast receives rain. However, the mountains prevent the rain from moving inland so rain shadow deserts form in these areas.
The Cascade Range and the Sierra Nevada Range run along the Pacific coast of the western United States.
The Atacama Desert is on the Pacific coast of South America.
Three important physical features found along the west coast of South America include the Andes Mountains, Atacama Desert, and Lake Titicaca. The Andes cover 5,500 miles along the west coast, the Atacama Desert is in Chile, and Lake Titicaca is in Peru.
The Atacama Desert extends into southwestern Peru along the Pacific coast.
Along the Pacific Ocean. (West)
The Andes mountain range runs down the Pacific coast of South America. It is the longest continental mountain range in the world, extending over 7,000 km along the western coast of the continent.
The Atacama is located along the Pacific coast of Chile and Peru.
The Sechura is a cool, coastal desert found along the Pacific coast of Peru.
Three important physical features found along the west coast of South America include the Andes Mountains, Atacama Desert, and Lake Titicaca. The Andes cover 5,500 miles along the west coast, the Atacama Desert is in Chile, and Lake Titicaca is in Peru.