The stratovolcano is composed mainly of andesite lava flows and breccias and was largely formed prior to the most recent major glaciation (Fraser Glaciation), which occurred between about 25,000 and 10,000 years ago.

composition of

Pennsylvania (Wikipedia) Pennsylvania (/ˌpɛnsɪlˈveɪniə/; Pennsylvania German: Pennsilfaani), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. Pennsylvania borders Delaware to its southeast, Maryland to its south, West Virginia to its southwest, Ohio to its west, Lake Erie and the Canadian province of Ontario to its northwest, the State of New York to its north, and the Delaware River and New Jersey to its east.

Mount Baker (usgs.gov) Snow and ice-covered Mount Baker, located in northern Washington, is the highest peak in the North Cascades (3,286 m or 10,781 ft) and the northernmost volcano in the conterminous United States.