Intelligence and Miscellaneous Articles. 235 



disseminated through those portions of the stone which were adja- 

 cent to the fissures occupied by the metallic mineral. Towards the 

 top of the section cakes of the sulphuret of lead were found in a 

 loose state, and exactly filling the irregular cavities in which they 

 were deposited. 



, The above description I received from one of the overseers and 

 from the men employed upon the road. As I was desirous of ascer- 

 taining as far as possible the truth of the account, T. Bunn, Esq. 

 of Frome, to whose love of science we are indebted for a know- 

 ledge of this interesting phaenomenon, had the road opened for my 

 inspection. The result verified the previous details. 



1 presume that this is the first instance in which galena has been 

 found in so comparatively recent a formation; but the connection 

 of the inferior oolite with the carboniferous limestone in that neigh- 

 bourhood, apparently affords data for attempting an explanation 

 of its occurrence. The latter rock is well known to abound with 

 lead. At Shipham near Axbridge, the dolomitic conglomerate, which 

 occupies a position analogous to that of the inferior oolite of Frome, 

 also contains numerous irregular veins which yield galena. In both 

 the newer deposits the situation of the metal accords with the cha- 

 racter of the stone. The inferior oolite possesses a natural tendency 

 to split into angular fragments, and in consequence of its great soft- 

 ness would divide with facility in their direction to every disruptive 

 force. The dolomitic conglomerate has no natural cleavage ; and 

 at Shipham is a rock of great hardness: it would therefore yield 

 only to a powerful agent, and then not in narrow fissures, but in 

 chasms of great diversity of form. 



When these circumstances are considered, — the metalliferous na- 

 ture of the mountain limestone, the total absence of galena in the 

 oolite, when other formations are interposed between it and the 

 older rock, — we may surely be permitted to conclude, that whatever 

 power, whether it were infiltration, infusion in a molten state, or 

 sublimation, by which the ore was deposited in the carboniferous 

 limestone, the same power acting cotemporaneously deposited it in 

 the dolomitic conglomerate and inferior oolite. From these partial 

 data we may likewise be permitted to draw the general conclusions, 

 that the age which has been assigned to metallic veins is too re- 

 mote; and that we may expect to find them, when our acquaintance 

 with the unconformable superposition of rocks shall be greater, 

 among the more recent of our secondary formations. 



ECONOMY OF TEREDO NAVALIS, &C. 



In the Report for the year 182G-7, of the Portsmouth and Port- 

 sea Philosophical Society, which has just been transmitted to us, ap- 

 pears the following report of a lecture, by Mr. C. Willcox, on the 

 boring and lithophagous marine animals ; containing some remarks 

 on the cuconomy of Teredo navalis, which seem to be important : — 



The habits and u--conomy of the Teredo navalis, the most 



destructive of the testacea, were described, and the irregular 



shape of the shell, description of the head, and formation of the 



2 H 2 liingt; 



