672 OX UPPER CAMBRIAN ROCKS IS SOUTH SHROPSHIRE. 



inquiries were leading him, as they seemed to point to the fact that 

 when there were no marked changes in lithological character in the 

 Cambrian rocks there was a recurrence or mixture of the forms of 

 life which elsewhere characterized better- defined horizons. He 

 asked the author whether the lower portion of his upper group of 

 grits and shales, with Orihis testudinaria &c., might not represent 

 not only Caradoc, but part of the Llandeilo, and whether in the 

 upper part of the lower group the Arenig beds also might not find 

 an equivalent, as he thought it improbable that in that area the 

 Caradoc would be found overlapping Llandeilo and Arenig and rest- 

 ing on Tremadoc. 



The Author, in reply to Prof. Hughes, said that the shales were 

 one homogeneous formation, marked throughout by the same fossils, 

 the younger types occurring in the same beds with the older forms, 

 and mixed indiscriminately with them. In the lower part of the 

 upper series, also, there were no signs of transition into an older 

 fauna, the species being common Caradoc forms. In reply to Mr. 

 Hicks, he pointed out that the Oleni which, as Mr. Hicks stated, 

 occurred in the Arenig, were of quite a different type from the 

 Shineton Oleni, which were antique forms, similar to those in the 

 Holgelly beds. 



