Original: How the discovery of geologic time changed our view of the world , Bristol University In 1977 , the Global Commission on Stratigraphy ( now the International Commission on Stratigraphy ) started an effort to define global references ( Global Boundary Stratotype Sections and Points ) for geologic periods and faunal stages .
Simplified: In 1977 , the Global Commission on Stratigraphy ( now the International Commission on Stratigraphy ) started an effort to define global references ( Global Boundary Stratotype Sections and Points ) for geologic periods and faunal stages .