layer cake federalism - traditional concept of federalism with clear and discernable boundaries between the powers of the national and state goverments. One level of government does not encroach upon or interfere with the other.

marble cake federalism - a more recent concept of federalism. State and national governments have established powers, but in practice these powers are shared and delegated to each other. (example: FBI criminal data files, EPA delegation of regulatory enforcement to state govts.)