513 



THE GEOLOGIST. 



remains, apparently spicula of sponges and Spiniferites, as may be seen 

 with a good microscope. The lower portion contains 



Nautilus radiatus Pecten orbicularis, two varieties 



expansus (?) very large quinque-costatus, common 



Ammonites rostratus (?) Ostrea vesicularis 



inflatus Casts of Venus or Thetis 



Ammonites, n. sp. Spondylus, sp. 



Belemnites lanceolatus Echinus (?) — two species 



Rhynchonella plicatilis Siphonia, Choanites, and other sponges 



octoplicata Bones and teeth of sharks and saurians 



subplicata Fossil wood 



At the bottom of one of the alternating beds of blue rag, large masses 

 of oval- shaped echinites occur in groups of from three to a dozen ; 

 they resemble the Amnchytes ovatus of the chalk. They are largely per- 

 meated with iron, and are so firmly embedded in the surrounding matrix 

 that to extract them is a work of great difficulty ; but it sometimes 

 occurs that the wash of the sea accomplishes that which the hammer 

 fails to do, and specimens are often thus brought to light exhibiting the 

 beautiful construction of the shell, and its division into the armour-like 

 plates of which it is made up. The author discovered a year or two 

 since, in these beds, a single vertebra of a large saurian, the Strepto- 

 spondylus (?), and it is now in the British Museum j such remains are 

 very rare. 



Fossil wood is common in these beds; it is white and silicified, but many 

 specimens are beautifully coloured by infiltration of iron. The author 

 has now in his possession a large piece of a longitudinal section of a tree 

 about eighteen inches in circumference, with the bark entire, which 

 is an inch thick, and of a brown ochreous tint ; the wood has annular 

 rings of growth, and is much perforated by boring shells. It is probably 

 dicotyledonous, and belonging to a cone-bearing species. It was 

 also from these beds that the fine specimen of Clatharia LyelU — 

 figured in " Mantell's Excursions," at page 217 — was obtained, 

 and not from the chalk-marl, at Bonchurch, as is there erroneously 

 stated, that specimen came from the ''great chert beds" in the 

 quarry above Steephill Castle, and was found by a workman whilst 

 excavating stone for building, and sold by him to Captain Ibbetson. 



Such portions of wood and vegetable remains as are found in the 

 Eomau Chalk of this locality,are always in such a decayed and decomposed 

 state, and in such small fragments, as to be utterly valueless for the 

 purposes of scientific determination. 



