Buchanan, who is buried in Lancaster, has regularly been ranked one of the worst presidents by historians, citing his ambivalence towards the South wanting to secede from the Union prior to the Civil War.
A shield volcano is a type of volcano usually built almost entirely of fluid magma flows. They are named for their large size and low profile, resembling a warrior's shield lying on the ground.
Shield volcanoes are a product of effusive eruptions. As the fluid lava flows out onto the surface, it spreads out and cools into a broad, low-angled slope. The final shape looks much like a warrior's shield with the convex side pointing towards the sky. The Hawaiian Islands are an example of shield volcanoes.ffusive Eruptions Effusive eruptions are those that create vast lava flows of low viscosity, fluid lava. Magma associated with effusive-type eruptions is relatively low in silica and thus easily flows up the vent and spreads across the surface. Moving across the land, these lava flows can take on two different forms.