280 OVERTHRUSTS AT TIHTAGEL. [-A-Ug. 1909? 



As to the unconformable overlap of the plant-bearing Culm grits 

 and shales on the Lower Culm and Upper Devonian, the evidence 

 obtained by the speaker in mapping the St. Mellion outlier seemed 

 to him to be conclusive. 



In conclusion he expressed his admiration for the beautiful piece 

 of stratigraphical work achieved by the Author. 



The Author, after thanking tbe Fellows of the Society for their 

 kind reception of his paper, in reply to Mr. Eeid's question as to 

 the date of the Tintagel overthrusts, said that he was unable to 

 assign definitely a date, but considered it not improbable that it 

 was pre-granitic. At the same time no pneuinatolytic minerals had 

 been found in the thrust-plane breccias, but only as veins of quartz 

 and schorl cutting across the strike of the beds, as at Trewethet 

 Gut. With regard to Mr. Ussher's question, the following fossils 

 had been found in the Tredorn Beds — Spirifer verneuili, Fenestella, 

 and traces of other bryozoa, which showed those beds to be of 

 approximately the same date as the Delabole Slates. 



