372 



COAL MEASURES — EASTERN CULM TRACT. 



culmiferous strata of Pembrokeshire are simply a prolongation of the southern limb 

 of the great South Welsh coal-field, which, extending from east to west, bisects the 

 county. Occupying at their eastern extremity the whole of Caermarthen Bay, they 

 appear in nearly an equal extent of coast cliff in St. Bride's Bay on the western, whilst 

 to the south of Haverfordwest, they are spread over a width of about three miles only. 

 In this range they are divided naturally into two parts by the north and south forks 

 of the great estuary of Milford Haven. To the east of the estuary, the coal strata 

 are regularly supported by girdles of millstone grit and carboniferous limestone, but to 

 the west the limestone rapidly thins out, being visible only for a short distance in broken 

 and disjointed patches. 



To obtain, therefore, a clear idea of the succession of strata in descending order, the 

 observer must examine the eastern or more regular tract, for example, at Amroth, to 

 the east of Tenby, where the youngest formations are exposed in the cliffs, and pro- 

 ceeding northwards he will successively pass over, 1 . Beds of shale and sandstone with 

 culm. 2. Hard sandstone and grit unproductive of culm, a prolongation of the 

 millstone grit of Caermarthenshire. 3. Carboniferous or mountain limestone. 4. Old 

 Red Sandstone. 5. Silurian Rocks. 6. Cambrian Rocks. (See PI. 35. f. 4. and wood- 

 cut, No. 72, p. 375.) All these masses rise from beneath each other in regular succes- 

 sion, and thus confirm the order which has been established by so many natural sections 

 in other parts of England and Wales. 



Culm at Landshipping. — In no place in Pembrokeshire are the culm-bearing strata arranged 

 with greater regularity than at Landshipping, on the east bank of the Cleddau, where they repose 

 upon unproductive shale and flagstone, which in descending order becomes gradually unproductive 

 of culm, the whole passing down into sandstone representing the millstone grit. This succession 

 is seen upon both banks of the river between Landshipping and Slebech, the transition from the 

 lowest and poorest culm seams to the hard flaglike beds without culm, being particularly well ex- 

 posed on the right bank, in the beautiful grounds of Picton Castle 1 , the strata dipping at slight 

 angles to the south. (PL 35. f. 3.) The overlying measures at Landshipping are very productive, 

 and have long been worked by regular shafts. The following is the descending order : 



Eastern Culm Tract. 



Section of the Coal works at Landshipping. 



Measures (shale, sandstone, &c.) 10 0 0 0 



1 . Culm or tumbling vein 0 1 0 0 



Fath. yds. ft. in. 



Fath. yds. ft. in. 

 ...0 5 0 0 



...0 0 2 0 



Measures 



Measures 7 0 0 0 



2. Culm or rock vein 0 1 0 0 



5 . Lower slate vein 



Measures (chiefly sandstone) 



5 0 0 0 



Measures 5 0 0 0 



3. Culm or slate vein 0 0 2 0 



6. Culm or north vein 



Measures (hlack rock and shale) 



0 0 14 



44 1 0 1 



Measures (hard sandstone and shale) ... 12 0 0 0 

 4. Culm or flint vein 0 2 1 0 



Dip 2 feet in 6, northerly. 



1 The property of Sir Thomas Phillips, Bart., M.P. 



