March 14, 1913] 



SCIENCE 



419 



Pleistocene while Volz, Carthaus, etc., con- 

 sider it middle Pleistocene. The two Selenka 

 expeditions to Java in 1906-07 and 1908 made 

 rather extensive excavations at Trinil and 

 brought back large collections of fossil plants. 

 These have now been described by Schuster,' 

 of Munich, and as the results are important 

 the readers of Science should have their at- 

 tention called to Schuster's conclusions. 



The exposure of the Piihecanthropus- 

 schichten at Trinil at the locality where the 

 human remains were found in 1893 is about 

 25 meters in thickness and consists of inter- 

 bedded conglomeratic tuffs, lapilli, ash-beds 

 and clays, partially fluvial or lacustrine and 

 probably partly eolian. Plant remains either 

 as leaf-impressions, lignite or petrified wood 

 are scattered throughout the section, occurring 

 most abundantly, however, in stratum No. 6 

 in the lower half of the section and at the 

 level at which Pithecanthropus erectus was 

 found. Eight species of fresh-water gastro- 

 pods were collected from member No. 4 above 

 the main plant bed, and waterworn bones 

 occur in member No. 5 which is above, and 

 No. 9 which is below, the main plant bed. 

 The main bone stratum. No. 9, contains a 

 meager fauna which is said to show affinities 

 with the Pliocene Siwalik fauna of northern 

 India. 



The flora described by Schuster comprises 

 fifty-four species, none of which are extinct, 

 distributed among twenty-two families. The 

 most abundant families are the Moracese and 

 Anonacese each with eight species, and the 

 Lauracese with six species. The geographical 

 distribution of these fifty-four species in the 

 existing flora is somewhat different from what 

 it was at the time of Pithecanthropus. Only 

 ten still flourish in the immediate vicinity of 

 Trinil although thirty-two or 62 per cent, are 

 still found on the Island of Java. Twenty- 

 nine or 57 per cent, are mainly Indo-Chinese 

 in the modern flora and one species, Uvaria 

 zeylanica of the Anonacese, is confined to 



' Schuster, ' ' Monographie der f ossilen Flora der 

 Pithecanthropus-Schiehten," Aih. Tc. Bayer. Alcad. 

 Wiss., math.-physik. Klasse, 26 Band, 6 Abhandl., 

 1911. 



Malabar, Ceylon and India. Schuster con- 

 cludes that this flora is of Pleistocene and not 

 Pliocene age, and there can be no question of 

 the correctness of this conclusion, since all 

 the forms are still existing, while in the upper 

 Pliocene flora of Mogi described by Nathorst 

 from this same general region 40 per cent, of 

 the species are extinct. Moreover none of the 

 Pliocene plants described by Crie from Java 

 are present in the present collection. Schuster 

 considers that this Pleistocene flora indicates 

 an annual rainfall of about 400 cm. and a 

 mean temperature of 64 to 68 degrees Fahren- 

 heit. If these deductions are legitimate they 

 show that temperatures were somewhat lower 

 than present-day Javan temperatures, while 

 the rainfall was somewhat greater than it is at 

 the present time. Schuster considers that this 

 Pleistocene flora flourished during a pluvial 

 period which corresponds to the Mindel or 

 second glacial period of Alpine glaciation ac- 

 cording to Penck's nomenclature, and that 

 Pithecanthropus erectus is slightly older than 

 Homo heidelbergensis discovered in 1907 by 

 Schoetensack at Mauer near Heidelberg, Ger- 

 many. Just how this exact correlation is 

 reached it is diflicult to understand; in fact 

 I hardly see how there can be any reliable 

 data for such a long range correlation. It 

 seems to me that the exact stage in the 

 Pleistocene is undeterminable. According to 

 Schuster's correlation the age is lower middle 

 Pleistocene, although he calls it old Pleisto- 

 cene. In the temperate zone a fossil flora with 

 no extinct species indicates a late middle or 

 upper Pleistocene age, but very likely this 

 does not apply with equal force to tropical 

 regions where the physical conditions have 

 been more uniform than in the temperate zone. 

 The three largest of the Sunda Islands- 

 Java, Borneo and Sumatra — are separated 

 from the Indo-Chinese mainland and from 

 each other by shallow seas less than one hun- 

 dred fathoms in depth and for the most part 

 not deeper than fifty fathoms. These seas 

 date from the submergence in the late Pleis- 

 tocene. In spite of this fact and the further 

 fact that the mountain axis of Sumatra also 



