394 



Dr. Whcelton Hind (^ John T. Stobbs— 



(xiii) A limestone quarry in the next field to the Axton Mine is 

 being worked at the present time, and from it we obtained — 



Cyathoplnjlliini Murchisoni, E. & H. P. scabriculus (Mart.). 



Monticuliporoid Coral. P. semireticidatus (Mart.). 



Feiiestella sp. Rhynchonella sp. 



Dielasma hastata (Sow.). Marti)na glabra. 



Productus aeuleatiis (Mart.). Spirifer yrandicostatus, M'Coy. 



P.fimbriatus, Sow. S. striatus (Mart.). 



P. giganteus (Mart.). Bellerophon sp. 



P. ptmctatus (Mart.). 



(xiv) At Trelogan the uppermost beds of the Carboniferous Lime- 

 stone have been very extensively quarried, and they are locally 

 known as 'Aberdo' limestone — this appellation being reserved for 

 limestones of exceptional value for the production of hydraulic 

 cement. In one of the quarries at this place we are fortunately able 





w 



S .to («i 



Horizontals, about 5^ inches to a mile ; verticals, 4-50 feet to an inch. 

 Fig. 1. — Diagram- Section Eastern flank of Halk}Ti Mountain. 



to see the position of the limestones in conjunction with the cherts, 

 A photograph of the section is shown in Plate XXI. where the erratic 

 pinching-out of the bands of black limestone may be observed. 

 The beds dip N.N.E. at 15°, forming the dip slope of the hill. The 

 succession is : — 



Cherts 20 feet + 



Limestone and shales ... 35 feet + 



The strata are singularly devoid of fossils, although several gigan- 

 teid Producti, P. costatns, and CampopliijUum Murchisoni were seen in 

 the bed of limestone immediately below the chert. 



(xv) A lower horizon is exposed at the surface at Garreg, where 

 a large quarry in white limestone is being worked at the present 

 time (hit. 53° 17' 45' N.. long. 3° 18' 10" W.). The uppermost bed, 

 12 feet thick, is of a deti'ital character, consisting mainly of crinoids. 



