144 Records of the Indian Museum. [Vol. XIV, 



a deposit of about 20 feet deep is exposed. It consists for the most 

 part of grey clay of great friability and composed of very minute particles 

 mixed with fragments of vegetable origin. This clay seems to be pre- 

 cisely similar to that now being deposited in the open parts of the Inle 

 Lake and we may take it that the deposit is of true lacustrine origin. 

 There is evidence, however, that conditions did not remain uniform 

 throughout the period of its deposition, for there exists, about 5 feet 

 above the base of the exposure, a layer of black peaty substance not 

 more than six inches deep. This layer must have been formed in con- 

 ditions different to those in which the friable clay was laid down and 

 points to a brief interruption in the formation of the deposit. The 

 whole exposure, nevertheless, is full of shells and no difference can be 

 detected between those above and those below the peaty layer. The 

 shells found in this deposit were : — 



Limnaea, sp. ? nov. Planorbis trochoidetis. 



Limnaea shanensis. Hydrdbioides nassa distoma. 



Tain lacuslris. 



The most abundant form was the Taia. Though in a rather brittle 

 condition and often broken, none of the shells were at all waterworn. 

 No other animal remains were observed. I think that the shells should 

 be regarded as fossil. The Hydrohioides, the Taia and possibly one of 

 the Limnaeae are extinct. 



Superficial Deposits. 



The superficial deposits of the He-Ho basin are of two kinds. Firstly 

 we have masses of exposed and usually broken shells lying on the banks 

 of the He-Ho river in sheltered places. The largest of these is on the 

 northern bank just above the point at which the stream plunges down- 

 Wards through a narrow gorge into the Inle plain. This deposit is sit- 

 uated a mile to a mile and a half east of the lacustrine deposit exposure 

 already described and lies at an altitude of about 3,600 feet, i.e., about 

 600 feet higher than the Inle Lake. To judge from the molluscs re- 

 presented in it, it is mainly a marginal deposit formed at the edge of 

 the old He-Ho lake. This is indicated in particular by the abundance 

 of shells of Succinea. Some of the shells are, how^ever, slightly Water- 

 worn. 



The species are : — 



Succinea indica. Hydrobioidts nuiSa distoma. 



Livinaea shanensis, Amnicola alticola. 



Planorbis saiqonensis, Taia theobaldi. 



Mdania baccata clongata. Taia intermedia, 



Ilydrobinides turrita. Taia lacustris. 



Corbicula noetlingi. 



No other animal remains were found, except a few land shells, which 

 may have been quite recent. They include a Plecfo])ylis still living 

 in the He-Ho gorge. Probably all the shells should be regarded 

 as subfossil. They include only two apparently extinct species, 

 namely Taia lacustris and T. intermedia. The race distmna of 

 Hydrohioides nassa is also extinct. 



