Yol. 62.] ROCKS OF WESTERN CARMARTHENSHIRE. 643 



above. This discovery by the Author appeared definitely to prove 

 the presence in South AY ales of beds of Glenkiln age, and suggested 

 the possibility of the shales overlying the limestone being referable 

 to the Hartfell Group. The Author's record of Dicranograptus 

 Clingani from these beds tended to confirm that supposition. 



The Author placed the Robeston-Wathen Limestone below that 

 of Sholeshook, and regarded them as calcareous developments of the 

 Dicranograptus -Shales and Redhill Beds respectively ; and this was 

 in agreement with the view expressed by Marr & Roberts in their 

 paper on the Haverfordwest district. 



Miss G. L. Elles remarked on the great skill shown by the- 

 Author in the working-out of a complicated area. He had sub- 

 mitted some of his graptolites to her, and the evidence afforded by 

 them merely confirmed the results arrived at by him on independent 

 grounds. 



With regard to the question as to how much, of the Dicrano- 

 graptus-Shales should be regarded as of Bala (Hartfell) age, she was 

 inclined to think that a considerable portion of them contained a 

 fauna more allied to that of the Llandeilo (Glenkiln). There 

 appeared to have been some confusion between Dicranograptus 

 rectus, a characteristic and common Glenkiln form, and Dicrano- 

 graptus Clingani, an equally-characteristic but far less common 

 Hartfell species ; hence beds containing a typical Glenkiln fauna 

 seemed in some cases to have been relegated to too high an horizon. 



Mr. H. H. Thomas, in reply, thanked the Fellows on behalf of 

 the Author for their kind reception of the paper ; he agreed with 

 Mr. Cantrill and previous speakers on the great importance of 

 the Author's work in so complicated a district. The Author fully 

 realized the great value of Thomas Roberts's work, which had been 

 of considerable assistance to him. The Author had submitted to 

 the speaker specimens of the igneous rocks from Llanboidy and 

 Dolwilyin, which are both ophitic diabase. The Llanboidy rock is 

 very much decomposed ; but the Dolwilym rock is much fresher, 

 and is characterized by the presence of pseudomorphs after a 

 rhombic pyroxene, a mineral not very common in the Pembroke- 

 shire minor dykes. It is likely that these masses belong to the 

 same intrusion, but this is impossible of proof, except from a study 

 of the field-relations. 



