50 Notes on Some Clay Concretions, 



is only external — is probably due to the different degrees of 

 hardness of the more minute strata of the beds in which they 

 are found, the more pervious strata allowing the seggregation 

 to push along their parallel lines, subsequent weathering giving 

 the strange resemblance some of them have to objects produced 

 on the lathe. 



After an examination of the specimens a series was presented 

 by the reader to the Museum. 



