Pleistocene The lower boundary of the Pleistocene Series is formally defined magnetostratigraphically as the base of the Matuyama (C2r) chronozone, isotopic stage 103. Above this point there are notable extinctions of the calcareous nanofossils: "Discoaster pentaradiatus" and "Discoaster surculus". The Pleistocene covers the recent period of repeated glaciations. The name Plio-Pleistocene has, in the past, been used to mean the last ice age. The revised definition of the Quaternary, by pushing back the start date of the Pleistocene to 2.58 Ma, results in the inclusion of all the recent repeated glaciations within the Pleistocene. The modern continents were essentially at their
Animation in the United States during the silent era Animation in the United States during the silent era Animated films in the United States date back to at least 1906 when Vitagraph released "Humorous Phases of Funny Faces". Although early animations were rudimentary they rapidly became more sophisticated with such classics as "Gertie the Dinosaur" in 1914, Felix the Cat, and Koko the Clown. Originally a novelty, some early animated silents depicted magic acts or were strongly influenced by the comic strip. Later, they were distributed along with newsreels. Early animation films, like their live-action silent cousins, would come with a musical score to be played by an organist