In a historical introduction the author gives an outline of the progress of research into the history of the Old Red Sandstone of the British area. This system is at present regarded as composed of three sub-divisions, Lower, Middle, and Upper, each characterised by a distinct suite of organic remains. From the absence of unequivocally marine fossils, and from lithological characters, it has been inferred by Mr Godwin Austin, Professor Ramsay, Professor Rupert Jones, as well as other observers, and is now very generally admitted, that the Old Red Sandstone, as distinguished from the “Devonian” rocks, probably originated in inland sheets of water.