484 



THE GEOLOGIST. 



free-stone proper, averaging four feet in thickness, and being about 

 tbirty-four feet from the top of the Upper Greensand." It is 

 succeeded by a thick bed of darkish-blue rag, and a bed of chert, the 

 last in the series. 



The 7th division has a depth of about thirty-nine feet, and is com- 

 posed of thick beds of fine sandstone, alternating with beds of blue 

 rag ; it may be divided into fifteen strata. The first is a bed of 

 yellowish sandstone, about three feet in thickness, fall of a species of 

 Sijyhonia, nodules with a sponge-like texture, remains of Polyparia, very 

 large dmmonites, Nautili, and nodules of rag. Below this is another 

 layer of rag, a foot thick, succeeded by a bed of fine sandstone of a 

 softer nature than the one above, and extending to a depth of about 

 three feet. 



In contact with the last is a bed of tough sandstone a foot thick, 

 locally termed the Black-band," and containing fossils. The writer 

 has now in his possession the claws of an Astacus (?), which must have 

 belonged to an individual more than a foot in length. He has, besides, 

 from this band, a species of Echinus (?). 



To this sandstone several alternating bands of light sand with thin 

 belts of the Black-band " succeed, the whole amounting to about seven 

 or eight feet in thickness. 



Below this, again, are stratified layers with nodules, termed Whill- 

 Kags," in shape like a compressed cone, many of which are two feet in 

 diameter, and most of them containing organic remains as nuclei. 

 They are very hard and tough, and difficult to break. They are, how- 

 ever, much used by builders in the construction of sea-walls, and for 

 the front-walls of dwelling-houses. On being cloven or split by the 

 quarrymen, by means of very large wedges inserted in a hole made by a 

 mallet and chisel, and afterwards driven in with a weighty sledge- 

 hammer, they are often found to contain Ammonites of very large 

 size, with the mouth entire ; and a fine species of Astacus (?) is reported to 

 have been thus obtained from one of them some years ago by Mr. Saxby. 

 The writer has seen some magnificent specimens of Ammonites in the 

 possession of Dr. Leeson, one of which, about sixteen inches in 

 diameter, was obtained whilst sinking a well at Bonchurch. It is, 

 perhaps, worthy of remark in this place that the fossils are generally 

 found at the base of the Whills." 



fTo he continued. J 



