145 



On the Occurrence of Miocene Limestones 



AT EDITHBURGH, and THEIR StRATIGRAPHIGAL 



Relationship to the Eocene of Wool Bay, 

 WITH Description of a New^ Species by 

 Professor R. Tate. 



By Herbert Basedoav. 



[Read July 2, 1901.] 

 Plate III. 



As far back as 1885 Professor Ralph Tate recorded and 

 described a few species of fossil mollusca from a sub-crystalline 

 limestone at Edithburgh, but was doubtful of its correct age. 

 He, however, thought it to be Miocene, as the difference between 

 its physical characters and those of an Eocene series a few miles 

 to the north of Edithburgh were marked, as also because of a 

 view adopted in the " Revision of Older Tertiary Mollusca" 

 1899. 



As this limestone has recently been quarried, an increased 

 number of species have been brought to light, consequently it 

 was thought desirable to reinvestigate this fossiliferous bed. I 

 submit more pronounced palieontological and stratigraphical 

 proofs that Miocene beds do occur at Edithburgh. 



A quarter- mile north of Edithburgh a deposit of polyzoal lime- 

 stone, containing such well-known and characteristic Eocene 

 fossils as Fibularia gregata, Scutellina patella, Paradoxechinus 

 novus, is found underlying yellowish compact limestones. Pebbles 

 are to be seen at the base of this compact limestone, and on close 

 examination they were found to consist of fragments of the 

 polyzoal limestone. This clearly demonstrates that the Eocene 

 bed must have been elevated into a land surface, suffered denuda- 

 tion, and, during a later period of subsidence, was covered by 

 the yellowish compact limestone. 



A clearer demonstration that such a sequence of changes did 

 occur is to be found in a splendid example of an erosion line 

 between the undoubted Eocene bed and those above it. At this 

 spot the top surface of the Eocene bed has an altitude of 26 feet 

 above sea level. About 200 yards further north the same Eocene 

 bed, still covered by the compact limestone, has a vertical height 

 of only six feet above sea level, and the erosion line exposed on 

 the face of the cliff between the two sections is well marked. 

 This erosion line extends southwards, exposed at intervals along 



