Is bedrock considered to be igneous?

Usually, bedrock is igneous, but in areas from Cairo, Illinois to Venice, LA and further south, bedrock is the first lithified sand or siltstone you hit when drilling. There's 8000 YEARS of river and bayou deposits creating 30,000 to 50,000 feet of saturated sub-surface in southern Louisiana. In 41 years I had more than 20 inches of sinking in parts of my New Orleans back-yard.