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Some beds of the Oolite of Yorkshire are remarkably rich 

 in minute organization. Abstracting the consideration of 

 the oviform grains, which in this rock are somewhat different 

 from the ova in the Bath Oolite, we find minute spines of 

 Echini, bits of shell, and plenty of small Foraminifera. 

 These latter are in fact numerous, and generally of the 

 form of Textilaria. Within a circle of l-40th of an inch 

 in diameter, we frequently find three of these beautiful 

 shells, the lamina which discloses them being less than 

 1 -200th of an inch thick. This would give, in one cubic 

 inch, 960,000 individuals, or one million wanting 40,000. 

 I have seen but few Rotaliae in this Oolite. 



Fig. 3 represents a beautiful section of one of the discoid 

 or Nautiloid Foraminifera, parallel to, but not quite through, 

 the axis ; the enclosing calcareous paste is there. The 

 transverse fibres, of which the shell consists, are visible. 



Fig. 4 is a minute spiral shell of a Gasteropod, (Turbo), 

 enclosed in a thin calcareous paste. 



Fig. 5. A portion of a species of Cidaris, enclosed in an oval 

 grain, which is formed of concentric sheaths of radiating fibres^ 



Fig. 6. A finger joint of an Encrinite, enclosed in a grain 

 of opaque granular calcareous paste, in which neither con- 

 centric sheaths nor radiating fibres are distinct. 



The Oolitic grains are separately suspended, so to speak, 

 in a connected mass of clear crystallized carbonate of lime . 

 and this circumstance is almost universally recognised in the 

 Oolites of the North of England. The Oolite of Ketton, in 

 Northamptonshire, is, in this respect, very different, being 

 mostly an ao^gregation of round grains in contact. 



In the chalk of Yorkshire occur, but far less frequently 

 than in that of Kent and Germany, minute Foraminifera, 

 especially of the genera Rotalia and Textilaria. I have 

 rarely found in it the spicula of sponges, or the minute 

 coralloidal bodies which are mentioned elsewhere. 



