Christy Mathewson (MLB HOF) played Pro Football from 1898-1902. More than two-thirds of the athletes who played at the top level of both sports did so in the early years of the NFL during the 1920s and 1930s.
Marine Terraces Marine terraces are formed by coastal erosion and reflect the history of the rise and fall of sea level over time. However, marine terraces are only found along coastlines where the land is rising. In areas where the land is sinking they are submerged or buried by younger sediments.
in marine ecosystem: Biological productivity. Primary productivity is the rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances. The total amount of productivity in a region or system is gross primary productivity. A certain amount of organic material is used to sustain the life of producers; what remains is net productivity. Net marine primary productivity is the amount of organic material... ...but differ in particular details throughout the biosphere.