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solicified. With a theory so complete and beautiful, it, however, 

 still remains to be explained how this sponge-like structure can bo 

 accounted for in the interior of a fossil, as in the case of a shark's 

 tooth, brought to the notice of the Geological Society by Mr. 

 Charlesworth. For further information on this interesting subject, 

 I beg to direct your attention to Mr. G, Dowkur's lecture, delivered 

 before our Society, and publislied with our annual report for 1877, 

 page 20, which embraces in an able and succinct manner most that is 

 at present known of the subject. Colonel Cox, of Fordwich, by 

 polishing sections of pebbles obtained principally from the Lower 

 Chalk has made a spkndid collection of fossil sponges, ventriculites, 

 choanitcs, &c., the structure of wliicli by this means becomes beauti- 

 fully apparent. Nodules of pyrites occur, especially in the grey 

 chalk, which also seem to be organised remains transformed into 

 the bisulpiiidc of iron, their shining golden appearance frequently 

 causing them to be used in the houses of the neighbourhood as 

 chimney ornaments, from whence they may find their way into the 

 fire, and surprise the uninitiated by burning with the blue flame and 

 odour of sulphur, red oxide of iron remaining behind. Some of 

 the best known fossils of the chalk are the echini, notably the 

 Anachytes ovatus, Galorites albogalerus, and Micraster coranguinum, 

 the two former popularly known as fairies' loaves, the latter as 

 serpents' hearts. One of the most beautiful of the bivalve shells, 

 the Lima spinosa, is also frequent, but very rarely is it found with 

 the elegant spines attached, to which it owes its name. All these 

 shells occur sometimes with the interior filled with chalk, at other 

 times with flint. The spines of the Lima occasionally may bo 

 found running through a flint, and in this manner preserved in one 

 of the most imperishable of substances. In the chalk pit near the 

 clump of fir trees just beyond the Chartham Lunatic Asylum may 

 be found fragments of the shell of a Pinna, which also occurs in the 

 Ramsgate cliffs, under which it may be picked up as the waves 

 wash it out of the chalk. It is locally called "beef and bacon," 

 from one side being of a brownish tinge and the other white. 

 This shell forms a good microscopical object. It is mentioned in 

 Gosse's Evening with the Microscope, page 50, and Dr. Carpenter 

 on the Microscope, page 590. In cutting the railway tunnel 

 through Lydden hill, a block of coal was found which weighed 

 about tour hundred weight. " It was embedded in the chalk 

 where the latter was free from faults. It was highly bituminous 

 and burnt readily, resembling some of the oolitic coals, but was 

 unlike the true coal of the coal measures." Mr. Goodwin Austin 

 believes it to have been a block of lignite carried into the 

 cretaceous sea by floating ice, in the same manner as it may be sup- 

 posed was the granite boulder, found in the chalk near Croydon. 

 In a paper by Mr. G. Dowkcr, publi.shcd in the Geological Magazine 

 for 1870, page 466, the author has done us the good seiwice to give 



