1918.] N. Annandale : Shells from Mesopotamia. 



161 



The shells had all been dead for some time and were quite opaque. 



The most interesting of these deposits, and also the most fully inves- 

 tigated, is that of the lake-bed near Nasariyeh, Colonel Lane has sent 

 me several diagrams to illustrate its position and structure, I reproduce 

 (in a slightly modified form) one of his drawings, which is of a section 

 of the deposit as seen in a trench. The sandy layers evidently represent 

 the sudden and repeated filhng in of the lake by sand-storms, the 



3 ft. 3 in 



6 in. 

 lin. 



8m. 



//////////////J///////////////J////) 



layers of clay (shaded) the bottom at different periods. There has 

 probably been some denudation of the surface. In the sandy layers 

 the shells are well preserved, while in those of clay conditions were un- 

 favourable for preservation and the only recognizable remains are those 

 of thick and heavy shells such as TJnio and the tests of Ostracods. 

 Fragments of vegetable matter are abundant in the clay. There is 

 some uncertainty as to which sandy layer many of the specimens are 

 from, but there is sufficient evidence that some of the species came 

 from all these layers ; the Potaniides and the Corbiila, brackish-water 

 forms, ^yere certainly found in the upper as well as the lower ones ; 

 most of these shells are probably from the 6 inch layer. All the thinner 

 shells from the deposit are dwarfed and many of those of Limnaea are 

 distorted, but this is also the case with many specimens from recently 

 inundated land in the same neighbourhood. Without examining fresh 

 specimens it is impossible to say whether all of the latter are recent. 



From a geographical point of view the most interesting feature of the 

 collection is the additional evidence it affords of the close relationship 

 between the aquatic fauna of lower Mesopotamia and that of the Jordan 

 valley. The abundant occurrence of Neritina jordani in the former 

 district is particularly significant in this connexion. 



