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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[Mar. 6, 



of Huddlestone, Bolsover, Steetly, and Roche Abbey are amongst tbe 

 most famous in the country*. 



Its maximum thickness must be about 200 feet or more. This 

 thickness it would appear to attain on the right bank of the Don, a 

 little to the south of the river. In other places it cannot be near so 

 thick, as between Hampole and the Great North Road ; indeed, the 

 variability in the amount of space between the outcrops of the Bro- 

 therton Beds and the Lower Limestone, allowing for difference of 

 position in surface, indicates a great variability in its thickness in 

 its north and south range. For this reason, and on account of its 

 irregularity of bedding, I am disposed to look upon it as having ori- 

 ginated in a comparatively shallow sea. Its general structure im- 

 plies the influence of currents of great inconstancy, and altogether 

 reminds us of that which may be supposed to characterize those sub- 

 marine banks, such as the " Dogger Bank " of the German Ocean, 

 that accumulate in water of no great depth, under the influence of 

 variable currents, at some distance from land. 



The Small-grained Dolomite can be easily examined in numerous 

 localties west of Doncaster, where it is well exposed in the pictu- 

 resque crags of the Don, and in the quarries that have been Opened on 

 the banks of that river. Amongst other localities may be named the 

 quarries at "Warmsworth, Levit Hagg, Cusworth, Outmoor, Cockhill, 

 Sprotborough, Boche Abbey, and Brodsworth ; the cliffs in the Yale 

 of the Went, and on the banks of the Don east of Conisborough. 



Professor Sedgwick notices it as occurring also at Mansfield, Bol- 

 sover, and Steetly further south, and at Huddlestone, to the north of 

 these localities. 



4. Lower Limestone. — Between the beds just described and the 

 * It should be remembered, however, that even this limestone, like all other 

 rocks of sedimentary formation, requires selection ; for intercalated among the 

 beds of good stone are others which do not possess the most important property 

 of capability to withstand atmospheric action. And not only so, but it is exceed- 

 ingly difficult to distinguish such beds from the best. It thus happens that a 

 certain percentage of stone of an inferior quality is often supplied to the builder 

 along with a large quantity of good, and is used by hini without suspicion of 

 the evil. I saw an illustration of this in the new church of St. George at Don- 

 caster, which is chiefly built of this limestone, where the surface of stray blocks 

 in the exterior was already in a state of decay when I visited it only one year 

 after it had been opened. Much of the stone used in the erection of the New 

 Houses of Parliament is from quarries (Huddlestone and Bolsover) of the Small- 

 grained Dolomite ; and it would seem as if stones from its worst beds had been 

 supplied rather extensively. For I cannot think that stone from its best beds 

 would ever have shown such signs of decay as it is asserted the stone of the river- 

 front of the palace already shows, even if we allow the atmosphere of the me- 

 tropolis to be very deleterious indeed. And, notwithstanding all the obloquy that 

 has been thrown upon the parliamentary commission appointed to select the 

 building-stone for fixing upon a magnesian limestone, and this in particular, there 

 can be no doubt they were right in their choice — the fault not being in the stone 

 chosen, but apparently in the neglect of the architect in not seeing that it was 

 token from the right beds. To obtain a good supply of stone of uniform good 

 quality, it is necessary to appoint some one at the quarry to select the beds to be 

 worked, and to see to the honesty of the contractor or quarrvman in working only 

 those selected, — the only difficulty being the requisite knowledge to deternfine 

 which are the superior ; and this, I conceive, is rather to be attained by long prac- 

 tical experience than from experiments in the laboratory. 



