AND EOCENE STRATA. 641 



Accordingly, I have introduced in the table, at p. 105, tlie name of 

 " Lower Miocene" as a synonym much in vogue on the Continent foi 

 strata of that age, called by me " Upper Eocene." It is unnecessary to 

 repeat the reasons so fully set forth in the text, which induced the late 

 Professor E. Forbes and me to employ this arrangement and nomencla- 

 ture in preference to one which throws into the same division the faluns 

 of Touraine (originally selected by me as the type of the Miocene) and 

 a fauna so distinct as that of the Fontainebleau Sands, which contains 

 no species of shells in common with the "feluns,"and which approaches 

 so nearly in the general character of its fossils to the typical Eocene 

 fauna. I observed, however (pp. 186, IS*/), that I was not unprepared 

 for the necessity of including hereafter the deposits above alluded to in 

 one and the same Miocene Period, should sufficient evidence be brought 

 to lio-ht of intermediate and counectino* links between the Fontainebleau 

 sands or Limburg beds and the faluns of Touraine. 



In the course of the last two years some progress has certainly been 

 made in bridging over the wide gulf which formerly separated the so- 

 called " Lower Miocene" from the " faluns," while on the other hand 

 the Eocene system is becoming so comprehensive and so complicated in 

 its details by the continual intercalation of new formations, and by the 

 addition below its former base of the Thanet sands and Lower Lande- 

 nian of Belgium, that the desirability of limiting its extension in an up- 

 ward direction is becoming more and more obvious. The Thanet Sands, 

 moreover, exhibit a testaceous fauna, almost as divergent from that of 

 the Barton clay as are the shells of the Fontainebleau Sands from those 

 of the faluns; so that, if we comprise the Thanet and Barton beds in 

 one Eocene Period, we may be called upon, with almost equal pro- 

 priety, to class the Fontainebleau and Falunian faunas in one and the 

 same great Miocene system. 



Professor Beyi'ich, in a recently published memoir on the tertiary 

 strata of the North of Germany,* has made known to us the existence 

 of a long succession of marine strata, leading almost gradually from 

 the equivalents of the Lowest Limburg or Tongrian beds of Dumont to 

 others appioaching in age the faluns of the Loire, Consequently he 

 has thought fit to introduce a new term — that of " Oligocene " — for all 

 the beds intermediate between Eocene and Miocene; and, having dis- 

 tributed the strata in question into seven subdivisions, each character- 

 ized by a certain proportion of peculiar fossils, he refers the uppermost 

 of all, or his Sternberg beds, to the " Upper Ohgocene ;" the next five, 

 comprising among others the Upper and Middle Limburg, to the "Mid- 

 dle Oligocene ;" and the remaining two to the Low^er Oligocene, com- 

 prehending the Lower Tongrian of Dumont with the Brown-coal of 

 Germany, which is classed as the lowest of all. 



M. Alcide d'Orbigny had previously (1852), in his Paleontology, con- 

 sidered all these " Oligocene" beds as a Lower Falunian division, class- 

 ing the faluns of the Loire as Upper Falunian. Dr. Sandberger, in his 



^ Abhandlungen der Konigl. Acad, der Wissen. zu Berlin, 1855. 

 41 



