Ch. XV.] MIOCENE STRATA OF SWITZERLAND. 249 



small skepticism liad always prevailed among botanists of the highest 

 attainments as to whether fossil remains of the vegetable kingdom 

 could ever afford sufficient data for determining the species, or even 

 the genera or families, of plants of which nothing but the leaves are 

 imbedded in the rocks. In truth, before such remains could be ren- 

 dered available, a new science had to be created. It was necessary to 

 study the outlines, nervation, and microscopic structure of the leaves 

 with a degree of care which had never been called for in the classifi- 

 cation of living plants, where the flower and fruit afforded characters 

 so much more definite and satisfactory. As geologists, we cannot be 

 too grateful to those who, instead of despairing when a task of such 

 difficulty was presented to them, entered with full faith and enthusi- 

 asm into the new and unexplored field. That they should frequently 

 have fallen into errors was unavoidable, but it is remarkable, espe- 

 cially if we inquire into the history of Professor Heer's researches, 

 how often early conjectures as to the genus and family founded on 

 leaves alone were afterwards confirmed when fuller information was 

 obtained ; as, for exam'ple, when the fruit, and in some instances both 

 fruit and flower, were found attached to the same stem as the leaves 

 which had been first described. Nor should we forget that when a 

 skilful botanist has devoted his powers of discrimination to the 

 classification of the leaves according to their forms, veining, and 

 minute or microscopic structure, he may afford the most important 

 palEeontological assistance to the geologist, even if he happen to make 

 some erroneous guesses as to the generic or even ordinal affinities of 

 the plants in question. His power of recognizing the same identical 

 fossil in two distinct places or two distinct formations may settle a 

 disputed point in chronology, where there is no other evidence at 

 hand, and the conclusions drawn from such data as to the relative age 

 of the beds have often held good, even when it was afterwards proved 

 that several species, or even genera, had been constructed out of the 

 leaves of the same plant, or that the fruit and leaves of one and the 

 same tree had been referred to genera of distinct families. 



The Miocene formations of Switzerland have been called Molasse, 

 a term derived from the French mol, and applied to a soft, incoherent, 

 greenish sandstone, occupying the country between the Alps and the 

 Jura. This molasse comprises three divisions, of which the middle 

 one is marine, and being closely related by its shells to the faluns of 

 Touraine, may be classed as Upper Miocene. The two others are 

 freshwater, the upper of which may be also grouped with the faluns, 

 while the lower must be referred to the Lower Miocene, as defined in 

 the last chapter. 



The upper freshwater Molasse may first be considered. It is best 

 seen at (Eningen, in the valley of the Rhine, between Constance and 

 Schaffhausen, a locality celebrated for having produced in the year 

 1700 the supposed human skeleton called by Scheuchzer "homo 

 diluvii testis," a fossil afterwards demonstrated by Cuvier to be a 



