Ch. XV.] UPPER EOCENE FORMATIONS. 185 



In 1851, I examined with care the Belgian formations at Rupelmonde 

 and Boom, near Antwerp, and in the Limburg, near Maestricht, and 

 was able, with the assistance of M. Bosquet, to give a table of no less 

 than 201 species of shells of the era under consideration. Of these more 

 than a third proved to be identical with English Eocene testacea, even 

 when I restricted the term Eocene to its most limited sense, extending it 

 no farther upwards than the Middle Eocene or nummulitic formations.* 

 For this reason I called the Limburg or Kleyn Spawen beds Upper 

 Eocene, giving as my reason " that they resembled the older formations 

 in their fossils as much as some of the different divisions of the Eocene 

 series in France and England resemble each other ; as much, for exam- 

 ple, as the Barton Clay in Hampshire agrees with the London Clay 

 proper, or the Calcaire Grossier with the Soissonnais sands in France." 



Subsequently, in the winter of 1852, Professor Edward Forbes exam- 

 ined near Yarmouth, in the Isle of Wight, a deposit occupying a very 

 limited area, but about 170 feet in thickness, which he first determined 

 to be of the same age as the Limburg beds. They were found to be in 

 conformable position with the other tertiary strata previously known in 

 that island, and to contain abundantly some of the most characteristic 

 Kleyn Spawen fossils. He named this deposit " the Hempstead series," 

 and classed it as Upper Eocene, for reasons similar to those which had 

 induced me so to name the Limburg beds of Belgium. They cannot in 

 fact be separated from the subjacent Eocene strata without drawing a 

 line of demarcation confessedly arbitrary, and which would leave a great 

 many of the same species of fossils above and below it. So complete, 

 indeed, is the passage from the Bembridge series (an equivalent of the 

 gypsum of Montmartre, and therefore an acknowledged Eocene forma- 

 tion) into the Hempstead beds, that Professor Forbes places both groups 

 together in his Upper Eocene division, drawing the line between Upper 

 and Middle Eocene at the base of the Bembridge beds. 



In opposition to this view two recent authorities, who in the course of 

 the present year (1853) have written on the tertiary formations of Ger- 

 many, M. Beyrich, before cited,f and Dr. Sandbeiger,J contend that all 

 strata, parallel in age with the Limburg, should be termed Lower Mio- 

 cene. M. Beyrich affirms that if the strata of the Bolderberg in Bel- 

 gium, and numerous deposits of contemporaneous date of Northern 

 Germany already enumerated (p. 178), be of the age of the "faluns," 

 then it can be shown that these same beds have so many fossils in 

 common with the Limburg strata, that the latter may fairly be regarded 

 as Miocene, or as an older deposit of the same great, period ; and he 

 goes on to say that, unless we are prepared to allow the Eocene division 

 to absorb all the overlying tertiary formations, we must begin a new 

 series from the base of the Limburg upwards, calling the latter Lower 



* Quart. Geol. Journ. 1852, vol. viii. p. 322. * 



f Die Conchylien ties Norddeutsch. Tertiargeb. : Berlin, 1853. 



% Uber das Mainzer Tertiiirbeckens, <fcc. : Wiesbaden, 1853. 



