The second subdivision (_B_) remains for consideration. Here the stature has not appreciably changed. The limb bones are long, slender, and less curved than those of the other associated human beings (_A_), and herein the earliest type is suggested once more. But the differences occur now in the skull. The brain is as large as in the other subdivision (_A_) and in modern men. The brain-case is becoming elevated: the brow-ridges are undergoing reduction; this process, commencing at their outer ends, expresses to some extent the degree of reduction in the muscles and bone of the lower jaw. The teeth are smaller and the chin becomes more prominent. The distinction from modern types of humanity is often impossible. In the next chapter some account is given of the circumstances under which the bones were discovered, and of the nature of their surroundings. CHAPTER III ALLUVIAL DEPOSITS AND CAVES The principal characters of the oldest known human remains having been thus set forth, the circumstances of their surroundings next demand attention. A brief indication of these will be given with the aid of the illustrations provided in the original memoirs in each case, and the order of descriptions followed in the preceding chapter will be observed. _Pithecanthropus._ The remains of Pithecanthropus were recovered from an alluvial deposit at Trinil. A section of this is shewn in Fig. 19. An idea may thus be gained of the very considerable amount of superincumbent materials. The associated fauna cannot be compared directly to that of any Western European locality. But in comparison with the modern fauna of Java, the strata in which the Pithecanthropus was found shew a predominance of extinct species, though not of genera. Elephants and hippopotami were present: they point to a close relation between the fauna of Trinil and that of certain Siwalik strata in India, referred to a late Pliocene age. The difference of opinion upon this point has been mentioned in the preceding chapter: here it will suffice to repeat that a final conclusion does not appear to have been reached, and that the experts who have examined the strata in situ still differ from each other. [Illustration: Fig. 19. Section of the strata at Trinil in Java. _A_ vegetable soil. _B_ Sand-rock. _C_ Lapilli-rock. _D_ Level at which the bones were found. _E_ Conglomerate. _F_ Clay. _H_ Rainy-season level of river. _I_ Dry-season level of river. (From Dubois.)]