Furthe}- Geological Queries. 233 



of a plug, nearly fitting the hole, by which operation the pores 

 of the stone are so closely plugged up, that when the Clay is 

 again bored o\it, the hole will remain free of water, for receiving 

 tlie charge of gunpowder in a proper cartridge. 



But I have been unintentionallv led into a long digression, 

 which I hope Mr. Wincii's goodness will excuse and permit me 

 to return, and mention, that 1 conceive we should not" naturally 

 consider," that basaltic eminences are anything else but the 

 thicker parts of a continuous stratum of Basalt, either actually 

 connected together by thinner parts in the lower grounds to- 

 wards the dip of the strata of the district, or are detached hum- 

 mocks, beyond the continuous edge of such a s^tratum, subject 

 to the anomalies common (in kind at least) of all other strata: 

 and to assure him, that 1 have never yet met with any single 

 instar.ce to the contrary : and with regard to Dykes I beg to 

 ask, 



Sth. Have the Wallbottle and Colcyhill Dykes wedged cut, as 

 practical Men sometimes say, or have their cheeks met, and the 

 fissures they occupied ceased, before reaching Montagu Main or 

 East Denton Collieries ? ; or, does a cross Jau/t or Dvke range 

 between the places mentioned, at which these Dykes terminate, 

 respectively, i)y joining into such cross fault ?. 



I perfectly join with Mr. Winch in concluding this head, that 

 in treating not on Basalt only, but on evcnj " peculiar species 

 of rock, one should be contented to speak of it only in situ:" 

 but this of course must not justify sjjei'.king or writing negatively, 

 in the closet, l)efore having examined every part of the surface^ 

 against inference from the facts of other districts. 



I beg re:>])ectful!y to press again my 3d request, for more pre- 

 cise localities of Muscle-shell Ironstone: I cannot admit, that 

 it is at all impossible to ascertain, to which of the particular 

 measures, in the numerous sinking accounts with which Mr. W. 

 has enriched the subject, the muscle-shells belong. The most 

 illiterate Sinker or Sougher, whom I ever meet with, among 

 some scores, on being shown a lump of the muscle-band, could 

 almost instantly say, whether he had or had not sunk through a 

 measure or bed thereof, in any particular Pit, of ins recent sinking, 

 and so of a Sough or Level, and if such Shells were found on his 

 hillock, could always sav, whence, precisely, they had been dug: 

 and the comparison of various such independent accounts, might 

 eiTectually guard against mistakes or im],>osition. 



I shall continue anxious to read Mr, Ws matured conclusions, 

 as to the passing of Red Marl (or its Sandstone) under tiie Alum- 

 shale, or otherwise, and hope nothing will occur to prevent the 

 <'om)jleti<m of his Yorkshire observations, and their speedy pub- 

 lication afterwards. 



To 



