It will be scarcely necessary for us to apologize for having given so much space to Stensen's work on geology. Many distinguished scientists, however, have insisted that no greater advance at the birth of a science was ever made than that which Stensen accomplished in his geological work. Hoffman says that after carefully studying the work, he has come to the conclusion that of the successors of Stensen, no student of the mountains down to Werner's day had succeeded in comprehending so many fruitful points of view in geology. None of his great successors in geology has succeeded in introducing so many new ideas into the science as the first great observer. For several centuries most of his successors in geology remained far behind him in creative genius, and so there is little progress worth while noting in the knowledge of the method of earth formation, until almost the beginning of the nineteenth century, though his little book was written in 1668 and 1669. Leibnitz regretted very much that Stensen did not complete his work on geology as he originally intended. Had he succeeded in gathering together all of his original observations, illustrated by the material he had collected, his work would have had much greater effect. As it was, the golden truth which he had expressed in such {160} few words, without being able always to state just how he had come to his conclusions, was only of avail to science in a limited way. Men had to repeat his observations long years afterwards in order to realize the truth of what he had laid down. Leibnitz considered that it took more than a century for geological science to reach the point at which it had been left by Steno's work, and which he had reached at a single bound. There is scarcely a single modern geologist interested at all in the history of the science who has not paid a worthy tribute to Steno's great basic discoveries in the science. It was not a matter for surprise, then, that the International Congress of Geologists which met at Bologna in 1881 assembled at his tomb in Florence in order to do him honor, after the regular sessions of the Congress had closed. They erected to his memory a tablet with the following scription: "Nicolae Stenonis imaginem vides hospes quam aere collato docti amplius mille ex universo terrarum orbe insculpendam curarunt in memoriam ejus diei IV cal. Octobr. an. MDCCCLXXXI quo geologi post conventum Bononiae habitum praeside Joanne Capellinio equite hue peregrinati sunt atque adstantibus legatis flor Municipii et R. Instituti Altiorum doctrinarum cineres viri inter geologos et anatomicos praestantissimi in hujus templi hypogaeo laurea corona honoris gratique animi ergo honestaverunt." [Footnote 12]