AMNIGENIA AND FRESH- WATER DEPOSITS 203 



decomposition relaxed the adductor muscles sufficiently to permit 

 the valves to gape. All lie at an oblique angle across the lines 

 of sedimentation and seem to have been exposed just ae they 

 died and were buried in their holes or washed into the mud at 

 the bottom of the coastal lake. This specimen has been pre- 

 sented to the museum by E. E. Davis esq. of Norwich N. Y. 



