Sept. 5, 1878] 



NATURE 



501 



THE PIKERMI AND SIWALTK FA UNAS 

 PLIOCENE, NOT MIOCENE 



'TPHE best zoologists are in the habit of calling the 

 ■■• mammalian fauna of Pikermi, in Greece, miocene. 

 As instances, I may quote Mr. Wallace in the " Geo- 

 graphical Distribution of Animals,'' p. 118, where it is 

 expressly stated that the mammalian remains in question 

 are " from the upper miocene deposits of Pikermi," and 

 Prof. Flower, in his paper " On some Cranial and Dental 

 Characters of the Existing Species of Rhinoceros," P.Z.S., 

 1876, in which he mentions, p. 457, "the miocene R. 

 pdchygnathus, Wagner, from Pikermi." 



I had occasion, a few days since, to consult Gaudry's 

 " Animaux Fossiles et Geologie de I'Attique," in connec- 

 tion with the Siwalik fauna — also persistently, but, I 

 believe, wrongly classed as miocene by European geolo- 

 gists and naturalists — and to my surprise I found it shown 

 by the clearest evidence, that this Pikermi fauna occurs in 

 pliocene beds, the age being proved by the occurrence of 

 niarine shells at the base of the bone-beds, and by the 

 circumstance that the strata containing both bones and 

 miocene shells rest unconformably on others with 

 miocene plants. The latter fact is less important than 

 the former, the value of plant remains for the determina- 

 tion of geological age being a disputed point, but no 

 geologist hesitates to accept the indications afforded by 

 marine annuals in preference to all others, and the 

 tertiary marine faunae of the Mediterranean area are 

 particularly well known. 



M. Gaudry proposes a hypothesis, op. c, p. 431, to 

 account for the presence of so many miocene forms in 

 pliocene beds. It must not be forgotten that several 

 Pikermi species are identical with forms found in un- 

 doubted miocene strata in Central and Western Europe. 

 The theory proposed is briefly that the Pikermi mammals 

 were driven into the hills by the breaking up of the 

 miocene land, and starved to death, when their bones 

 were washed down into the bed with pliocene moUusca. 

 As there must have been, I think, a long interval of time 

 between the deposition of the disturbed miocene beds and 

 the formation of the unconformable pliocene strata, I 

 think the following suggestion is preferable, as it avoids 

 the idea of any sudden change. There is abundant evi- 

 dence that the refrigeration of the earth's surface, cul- 

 minating in the glacial epoch, commenced in pliocene 

 times, and this may have led to a southern migration of 

 the mammalia, so that animals which, in the earlier 

 epoch, inhabited Central Europe, at a later period still 

 survived in Grece, although they had been replaced by 

 pliocene forms further north. It has already been 

 shown by various writers that there is a connection 

 between certain miocene faunas in Central Europe and 

 the living mammaha of Africa on the one hand, and of 

 the Malay countries on the other, and I think it not im- 

 probable that the remains found in pliocene beds in 

 Greece, and at the base of the Himalayas, owe their 

 miocene affinities to the same facts of migration to which 

 similar affinities may be attributed in the living forms. 

 _ The evidence of the pliocene age of the Siwalik is 

 simple. In Sind strata containing miocene marine 

 fossils pass up into beds with a mammalian fauna, in- 

 cluding some of the older Siwalik forms, such as 

 Mastodon, Chalicotherium, Dorcatherium, &c., together 

 yf\i\i Dinotherium, Hyopotamus, Hy»theriu7n, Anthraco- 

 therium, &c., which have never been found in the true 

 Siwaliks. These Sind beds are apparently equivalent 

 to the lower Siwaliks, which are unfossiliferous in the 

 typical area. In the middle and upper Siwaliks, instead 

 of the old forms just named, Ekphas, Loxodon, cervine 

 and bovine ruminants in abundance, and other recent 

 types are found. Now, as the Sind beds cannot be older 

 than upper miocene, the typical Siwahks must be pliocene. 

 The mammal Bos {Bubahis) palceindicus, found in the 

 upper Siwaliks, occurs also in the Nerbudda alluvium, 



where it is associated with palaeolithic implements. It is 

 not credible that a mammalian species could have lived 

 from miocene to post tertiary times. 



The question of the true age of these later tertiary 

 mammalian fauna is of such vast importance in the 

 attempts now being made by many naturalists to work 

 out the line of descent of living animals that I trust I 

 may be pardoned for calling attention to the preceding 

 facts. w. T. Blanford 



OUR ASTRONOMICAL COLUMN 

 Schmidt's Charte der Gebirge des Mondes.— In 

 the Introduction to the Erlduterungsband, accompanying 

 Prof. Schmidt's lunar charts, he has given an interesting 

 account of the progress of his great work, of the difficulties 

 he encountered, and the assistance afforded him in a 

 variety of ways, until the honourable and flattering con- 

 clusion. It was in the autumn of 1839, at his native 

 place, Eutin in Holstein, that his attention, at first given 

 to botany and zoology, was directed to the moon, by the 

 circumstance of a copy of Schroter' s work having come 

 into his hands through a sale by auction. The engravings 

 of the numerous craters and mountain-shadows made so 

 strong and lasting an impression upon his mind that he 

 appears to have resolved to make the study of the surface 

 of our satellite the principal aim of his life. At fourteen 

 years of age the possession of a small draw-telescope, 

 constructed by his father, enabled him to commence his 

 observations of the lunar features, and his first sketch 

 was one of the well-known streaks of Tycho, made with 

 this instrument, which was supported against a street 

 lamp-post ! A stand being subsequently provided, he 

 began to draw whole phases, in which Mayer's charts 

 were found of service. Thus he observed in 1840, his 

 school studies, as he tells us, suffering thereby not a 

 little. As so often happens in similar cases, young 

 Schmidt's peculiar bent attracted the attention of one 

 who had the disposition and the means to aid him, and 

 State-Councillor Hellwag, a highly-educated man, with 

 advanced knowledge of astronomy, provided him with a 

 very perfect telescope by DoUond, and with it he observed 

 at Hellwag's house. In July, 1841, he saw the moon for 

 the first time in a large telescope, Petersen, assistant 

 to Schumacher at Altona, having shown him the crater 

 Gassendi and Bullialdus. He then learned first, as he 

 says, the richness of the lunar formations, the more that 

 he became acquainted at this time with the large chart 

 of Madler. In 1842 Schmidt went to Hamburg, 

 and obtained access to the observatory under Riim- 

 ker' s charge ; here, through the good- will of the 

 director, he made use of various telescopes in fur- 

 therance of his lunar work during the years 1842-45. 

 In June, 1842, he was also assisted by Herr Bartels, 

 of Hohenfelde, near Hamburg, who allowed him the use 

 of his telescope, and it was at this time that he made 

 the earliest drawings which proved available in the con- 

 struction of his great chart. In 1845 he went to Bilk, 

 near Dusseldorf, the site of Benzen berg's observatory, 

 but his progress was slow here, the principal instruments 

 originally in the building not being then serviceable. 

 During his residence at Bonn in connection with the 

 observatory presided over by Argelander, this continued 

 to some extent, the regular work of the establishment 

 claiming attention ; nevertheless in the period 1845-1853. 

 he obtained sketches which proved of value, with written 

 descriptions of many of the features of the moon's sur- 

 face. On several occasions during this interval, by the 

 encouragement of Profs. Galle and Bruhns, he had oppor- 

 tunities of making drawings with the aid of the Berlin 

 9-inch refractor. From 1853 to 1858, Schmidt had charge 

 of the observatory of Herr v. Unkrechtsberg, an eccle- 

 siastic at Olmiitz, and here he undertook micrometrical 

 measures for determining the heights of the lunar moim- 



