The Gosau formation, nearly corresponding in age to the Upper Greensand of this country, is represented at Neue Welt, near Wiener Noustadt, by freshwater deposits full of such freshwater shells as Melania and Unio, and land-plants such as Banksia and Pecopteris. The formation and its fauna have been described by Profs. Suess, Zittel, and many others; but, although the late Dr. Stoliczka detected a tooth imbedded in the coal of the formation, no important knowledge was obtained of the vertebrate fauna of the Gosau beds until Prof. Suess was so fortunate as to obtain the assistance of Bergverwalter Pawlowitsch in conducting excavations. These were carried on with admirable skill; timber drift-ways were driven into the rocks, with the result that they penetrated into a perfect cemetery of the remains of Cretaceous reptiles. The remarkable collection thus obtained was intrusted for description to Dr. Emanuel Bünzel, whose memoir upon it was published in 1871 in the ‘Transactions of the Imperial-Royal Geological Institution.’ Subsequently more specimens were discovered; and in Easter 1879 my honoured friend, Prof. Suess, invited me to visit Vienna to examine these specimens, with the object of making them available for the advancement of knowledge by publication. With the assistance of the Royal Society I gladly undertook this work, and spent a month in Vienna studying the thousands of fragments which had been obtained. The great, mass of these, mere comminuted bones, proved of but little value; or, rather, the time that I could give to their study enabled