242 J^- >'ISHIWADA : ORGAXIC REMAINS FROM THE 



n) The Upper serie.s is of vast extent, covering' most of the 

 soiitliern part of tlie province of Tötömi, and is overlaid discordantly 

 by the not-less-widely distributed Qiiateriiary forniati(jn. It consists 

 of shale, sandstone, and conglomerate, all of tnficeous nature, and 

 yields a number of fossil shells. Amongst them are species oï Xassa 

 japonica Adams, Lauipnnid :o;/rt//'.s' Lamarck, Ccrilhiuw, Chcmnitzia, 

 Tiissou, TcWnui iiasuta Conrad. Pefricohi, Corhula, Area tjranom Linn('^, 

 Ostca <ji<jn^ 'riiund)erg efc,' 



Judging from tliese shell remains, the Upper series may be con- 

 sidered as contemporaneous wifh the Pliocene Tertiary developed in 

 the environs of Tökvö. a detailed account of which is found in Dr. 

 Ijrauns' Geolorm of tlic Eiir Irons of Tölnjö. 



Overlaid by the PHocene Tertiary just described, there lies b) 

 the Lower series occupying a very limited area. It is m:iinly made 

 up of dark -greyish shale and brownish or greyish sandstone — ^^just that 

 alternation whir-h is found overlying the limestone, as already described. 

 With the exception of the limestone, this series has yielded so far 

 no harvest of any characteristic fossils for the determination of its 

 geological age. According to the order of superposition, however, 

 tliere ca.n be no reasonable doubt that this division is older than the 

 Upper one, so that it will b' admitted that the limestone may belong 

 to some older epoch than the Plioceije. 



Xow. |)utting out of account the other remains in the limestone, 

 we know that /.. raDiosissimuni Reuss has hitherto been found in the 

 Miocene Tei'tiary and in no other formation. Hence, the recurrence 

 of this species in tlie limestone, togetlier with the f-.u-t that the rock 

 is overl'dd discordantlv by the above-mentioned Pliocene strata, 



1. Loc. cit. p. IG. 



