Vol. 54.] LIMESTONE OP THE COUNTRY AKOUND LLA.NDTJDNO. 385 



Compared with the Carboniferous Limestone for 50 miles to the 

 south-east this section is remarkable, for with the exception of the 

 outcrop of Little Orme's Head the Lower Brown Limestone is not 

 composed of dolomite, either about Llandulas, the Yale of Clwyd, 

 or in the country around Holywell, Mold, and Llangollen. There is 

 no indication of the Red Basement Beds around Llandudno, although 

 they are well exposed near Llandulas and in Anglesey. 



The highest beds of the Upper Grey Limestone at the top of the 

 Head have been denuded, and there is no trace of the succeeding 

 Upper Black Limestone of Prestatyn, or of the Purple Sandstone of 

 the Yale of Clwyd, both of which are on about the same horizon. 



(1) Lower Brown Limestone. 



Although I have not been able to find the base of the limestone 

 anywhere about Llandudno, Mr. H. C. Beasley happened to see an 

 excavation for the foundation of a house, on the north side of 

 Chapel Walks, in April 1886, and he recorded the following section 

 of the beds, which dipped to the north-west : — 



Section at Llandudno -r^ , 



Feet 



Thin sandy beds alternating with limestone 3 to 4 



Soft calcareous sandstone, with plant-stem 1 



Fine-grained limestone, with one or two subangular, hard, black 



pebbles 1 to 2 



Breccia of subangular pebbles, very firmly cemented together — the 



upper surface of the bed very uneven 1 



Limestone ? 



The section seems to have been on the south side of the supposed 

 fault running W.IS'.W. and nearly parallel with the ' Old Eoad ' 

 which runs up the hill from Llandudno. As no such section occurs 

 on the beach about the Pier, it seems certain that the beds that 

 were exposed are nearer the base of the Lower Brown Limestone, 

 and that they may have been brought up by the fault just mentioned. 

 It is fortunate that the observation was so carefully made, as there 

 is only a remote chance of any such exposure being seen again. 

 Mr. Beasley found the following fossils in the excavation : — Belle- 

 rophon sp., Productus Cora^ Spirifera glabra, and Lepidodendron (?), 

 and they were submitted to me for determination. In a ' Guide to 

 Llandudno,' by John Heywood (undated), it is stated that ' In an 

 old quarry, once a sea-beach, at the foot of Great Orme, near 

 Church Walks, Stigmaria and Lepidodendron may be found in situ/ 

 and this no doubt relates to the same exposure. 



The Lower Brown Limestone or Dolomite is the lowest subdivision 

 at Great Orme's Head. It is well exposed in the precipitous cliffs 

 above Llandudno, on the road above the Pavilion to the Happy 

 YaUey, and at the Flagstaff 100 yards north of the Lodge. The rock 

 varies from a coarse to a fine-grained dolomite, which in many places 

 simulates a mass of coral, and there are frequent drusy cavities con- 

 taining crystals of pearlspar. It closely resembles the Permian 

 limestone of Sunderland, and is of the same massive and crystalline 

 character. 



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