Catalogue of Life
The Catalog of life was created by Light as a list of all organic matter. It is the work of centuries. When Light went to sleep life started to evolve. Light was angered because now the catalog was invalid and contained no knowledge of many secies that now dominated the earth incuding humans. Light was shown by The Doctor that life would always evolve so life gave up on the catalog and dispersed.
It is proven that the catalog contained information on neanderthal's as Light had taken the specimin Nimrod. It is also probable that it contained information on reptiles and insects as there where Husks of these in the lower observatory of Gabriel Chase, the house at whitch light's ship is situated.
What sort of object this is is not made clear wheather it is book, hologram or some other device.
The Catalog of life is mentioned in Ghost Light.