-530 MISS CEOSFIELD AND MISS SKEAT ON THE [Aug. 1 896, 



: shales are lighter in colour, brittle, and extremely fissile : here the 

 fossils are most plentiful. We obtained Didymograptus Murchisoni, 

 Beck, Orthis testudinaria, Dalman, Lingula, and Orthoceras. Near 

 'the top of Merlin's Hill is a small quarry of the same shales, which 

 are much weathered, and the fossils are not found on the cleavage- 

 . faces. 



5. Llandeilo Limestone. 



There is no Llandeilo Limestone in the district, but, as already 

 suggested, this formation may be represented by the gritty and 

 sandy flags, which are found at the northern limit of the Didymo- 

 graptus Murchisoni-sh&les. In these beds we found Asaphus 

 tyrannus, Murch., and Orthis striatula, Dalman ; but we have not 

 attempted to separate them from the lower ones. The limestone 

 that is used for agricultural purposes is brought from a distance, 

 and is mainly of Carboniferous age. 



6. Dicranograptus -shales. 



These beds are dark blue or black in colour, soft and well 

 •cleaved. They are seen to dip over the Didymograptus Murchisoni- 

 ;shales, but the actual junction with the lower beds has not been 

 determined. Fossils are rare except in occasional bands, and can 

 ibe obtained only in a fragmentary condition, as the rocks are 

 generally cleaved at an angle with the bedding. The shales are 

 best seen on the Cardigan Road, and are exposed for about J mile 

 from Cwarebach on the south to near Pantau on the north, where 

 they dip under a great series of hard, unfossiliferous, silvery-grey 

 -flags. The fossils obtained from this exposure wore Olimacograptus 

 Mcornis, Hall, and Diplograptus, sp. 



Confirmatory Sections. 



The beds may be traced in several sections westward. At Cwm- 

 du-Mawr and Allt Llyn Teg the beds are black and sometimes very 

 carbonaceous. They yielded Diplograptus foliaceus, Murch., and 

 D. dentatus, Brongn. At Felin Fach quarry and in the lane near 

 the Plough and Harrow Inn, where the rock closely resembles that 

 of Cwm-du-Mawr, the same fossils occur. Near Glan-yr-Afon in 

 the same road, but a mile to the north, Diplograptus foliaceus, 

 Murch., was found. Between these last-named exposures we have 

 a series of unfossiliferous, soft, pale-grey satiny shales cropping 

 out, which is considerably folded, and of the age of which we are 

 ignorant. 



In a quarry near Tan-yr-allt Farm, on the western slope of 

 Llangunnor Hill, are pale-grey slates, weathering brown, inter- 

 stratified with hard micaceous striped slates of a gritty texture. 

 The beds are very barren, but yielded one specimen of Dicrano- 

 graptus, sp., cf. ramosus, Hall. 



