246 Rev. James Yates on the Structure of the 



on its north-eastern side by an almost perpendicular precipice, and said to 

 consist of trap rocks. 



On the "higher" road from Bishop's Castle to Ludlow, and near the lime- 

 stone range of Wenlock Edge, is situated Long Lane Quarry, at a little di- 

 stance above "the Craven Arms." The rock is a fine sandstone, occurring; 

 in strata of considerable thickness, and used in all the surrounding country for 

 building : it occurs also in the form of large thick flag-stones ; its colour is a 

 greenish gray ; it contains portions passing like veins through its substance, 

 which are of a rusty brown colour, and are full of the cavities formed by small 

 terebratulae and other shells, the matter of which has been removed. These 

 brown veins chiefly accompany the divisions of the strata, and the cleavages 

 perpendicular to them. The shells have been more thickly deposited in their 

 substance than in the rest of the rock ; the greenish portion of the rock effer- 

 vesces abundantly in muriatic acid ; it may be called a calciferous sandstone. 

 Small particles of malachite and iron may be observed intermixed with the 

 sand, and probably the colour of the rock may be attributed to the presence of 

 these metals : the various appearances may be explained by supposing the 

 carbonate of lime to have been deposited from a state of solution in the same 

 fluid, which contained the granular and sandy portions mechanically suspended. 

 This fluid must have contained also the shells found in the rock, and would 

 deposit them in the greatest abundance in situations contiguous to the present 

 surfaces of the successive strata. After the consolidation of the calciferous 

 sandstone thus produced, another fluid must have penetrated it by following 

 the course of the divisions of its strata and of its cleavages ; this fluid must be 

 conceived to have been a solvent of carbonate of lime, and to have removed, 

 as far as it penetrated, both the substance of the shells and the calcareous por- 

 tion of the sandstone, at the same time altering the colouring matter. The 

 strata of Long Lane Quarry dip to the S.E. at an angle of about 20° to the 

 horizon ; if continuous, they must dip under the limestone of Wenlock Edo-e. 

 The same rock, sometimes more siliceous and argillaceous and sometimes 

 more calcareous, occupies all the country as far as the vicinity of Ludlow. 



The rock to the west of Ludlow, in the picturesque grounds of Downton 

 Castle, is of the same kind with that on which Ludlow Castle stands, and which 

 is also exhibited in large quarries opposite the Castle. The cliffs which over- 

 hang the Tame in this demesne, are in many cases divided in the direction of 

 their natural joints or cleavages into the same rhomboidal forms which have 

 80 often been noticed. In other cases the effect of atmospheric decomposition 

 has been to exhibit great oval masses in the midst of the shattered fragments 



