Mr. J. Blackwall's Ohservatio7is on the Flouse-Spider. 95 



state a similar appearance, in its specimens of burnt, yellow 

 and red clay, and white and red clay-stone, to that at the point 

 (b.) And in the present month of September, I also found that 

 at the point (d) there had been a considerable portion of the 

 cliff under combustion; and large fragments of slag and vitri- 

 fied clay-stone were picked up on its sui'face. 



The circumstance of these three points b, c, and d being situ- 

 ated each in the immediate vicinity of coal-beds, renders it 

 highly probable that their combustion is to be attributed to a 

 subjacent seam of coal having become ignited, and communi- 

 cating its flame to the inflammable materials with which they 

 were supplied. 



I may here observe, that after a strong south-east gale the 

 shore on this coast is strewed both with small and large 

 rounded fragments of pumice-stone, of four varieties of colour ; 

 white, ash-gra}', brown, and black. In its texture this pu- 

 mice bears a striking resemblance to that variety of this 

 mineral which abounds on White Island, aconstantly active 

 volcano, 4-0 miles to the north of the East Cape of New Zea- 

 land ; and it may be a c]uestion of interest, whether these frag- 

 ments of pumice are conveyed to these shores from thence, or 

 detached and borne on the waves from some submarine vol- 

 cano in our more immediate neighbourhood. 



The strand on this coast, in many parts composed of sand- 

 stone, millstone-grit, and pudding-stone, mixed with ironstone, 

 is singularly divided in several instances into sections resem- 

 bling rail-roads; and in one spot it is covered with circu- 

 lar masses, much water-worn, in figure resembling those of 

 a curious formation of sandstone discovered by me in Glendon 

 Brook, Hunter's River, and described in a memoir read be- 

 fore the Philosophical Society of Cambridge in the month of 

 March 1830. 

 Sept. 23rcl, 1831. 



XXI. Observations on the House-Spider, iji repty to a State- 

 ment in the Zoological Journal, quoted in the Phil. Mag. 

 and Annals, vol. x. p. 184'. By John Blackwali,, Esq. 

 F.LS. 8fc* 



"I^UMEROUS experiments made with the House-spider 

 *• [Aranea domcstica), under a greatvarielyof circumstances, 

 have mduced me to believe that it is not endowed with the 

 instinct to let out lines from the spinners, over which it can 

 escape from captivity, when placed on a I wig insulated by 

 water and exposed to a current of air. This opinion, which 

 is published in the Philosophical Magazine and Annals, vol. x. 



* Coramunicated by the Author. 



