CIIAPTKK V. 



Till-; TKUTIAUY HKlNtSlTS WITIIIS IIIK I'KKCINlTS oK TdKIo. 



One locality alliulo;! to in thu Foc<«rl chiipk-r, situitc I at tlio ftnit uf the 

 iii|jj;cs liL'twcin Oji ami that \\\\t of Tokio which is c.illc;l Uycno, anl containinrj 

 only siK-h ti'iliary fossils as have been rclt'iiosilcil in alliiviil l.iyci'8, h:is fnrnishe;! 

 a certain niinibcr of spiHiiniens of shells raentionel above (Teliini iiitiit.i Conr., 

 Dosinia cxoleta L, Ostrea gigas Tlinnb., Saxiilunms iinri>nratiis Sow., Aa-.i in- 

 llati Ileeve), but no si>eeies which is not contained in (ho Oji layei"s, an! therefore 

 it may 1x3 dismii^sed here. Another exposure shown to me and situated in the 

 north-western jurt of Tokio, and s;iid to have formerly exhibited the ghell-layer, 

 diK?s not show any trace of it now, dee|) thongh the cutting of the ixjad is 

 which in this ])1 1 -j leads down from the jilateau to one of the tracts of low 

 gromi 1. iSiniilar is the e;isc of the well-diggings often meiilionnl and almost 

 always reaching tho terti iry shell-bj 1. The only locality therefore, whieli 

 remains to be mentioned in the northern jiirts of Tokio, is Surugilai. 



Sl'UrCADAI. 



I'ctween Surng.ilii and Seido, at a short distance from Nihon-l'ashi to the 

 north, theiv is a very deeii cutting through which the c m il of Kandigiwa g<K'S. 

 This cutting and the canal itscdf sepiinte Rnnigadai from the Rstof the diluvial 

 plateau and isolate this proj„vting pirt of it. The entiix; hill of Sunigadai is 

 said by .some authoi-s to have b^en the ix'Mih of the construction of the c.mal 

 which took pla-e in the 17th century. This assumption is improbable on account 

 of the great extent and lieight «if the hill, which exactly ctpials tlie plateau on 

 the other side of the canal; and it becomes entirely untenable after an examina- 

 tion of the steep s'opL's of the cinal-cutting. l''or there we see native nx-ks 

 outcropping on the banks <if either siile which jierfeetly corresfK)nd to one 

 another. The deeper layers arc uneomformably covered by horizontal stmta rich in 

 jKjbbles, but partly elayi.sb, which are tJicmselves covcR'd by the upper diluvial 

 loam. The thickness of l)oth of these parts of the diluvial formation and their 

 dist;uice from the upjier margin is, of course, by no means unifonn; the follow- 

 ing nieivsurement, made in tliat part of the nortlieni slope where the lower stmta 

 are richest in fossil shells, m.ay lie taken as an average. The soil, however, lias 

 l)ecn removed there to mme extent near the ujuwr margin, a road Ix-ing led over the 

 height and dee|iened imder the original surface. Ikdow the level of the road, 

 T found r> meters of the iipjH-r diluvi.d lo.am; 4 metci-s of lower diluviinn with 



