NOMENCLATURE OF " MICROSCOPIC OBJECTS " ETC. 131 



XV. Corrections of the Nomenclature of the Objects figured 

 in a Memoir " On some of the minute Objects found in 

 the Mud of the Levant" $c*. By Professor W. C. 

 Williamson, F.R.S. 



Read April 30th, 1872. 



In 1845 I laid before the Manchester Philosophical Society 

 a memoir " On some of the Microscopic Objects found in 

 the Mud of the Levant and other Deposits ; with Remarks 

 on the Mode of Formation of Calcareous and Infusorial 

 Siliceous Rocks. " This memoir was written at the period 

 when the microscope was opening out a new world alike to 

 the zoologist, the botanist, and the geologist. The study 

 of the Foraminifera was beginning to assume its modern 

 scientific form ; and the objects now so familiar to us as 

 Diatomacese were being discovered at innumerable locali- 

 ties ; so that we were entering upon that harvest of beau- 

 tiful organisms which we have since reaped in so abundant 

 a measure. 



But, as was inevitable in the infancy of these studies, 

 our views on many points connected with them were vague 

 and unformed. The memoir in question constitutes one of 

 the earliest of the attempts made to give scientific shape to 

 a number of important problems, especially dealing with 

 the nature of the Foraminifera, demonstrating the organic 

 nature of some sea-beds and the almost invariable organic 

 origin of Limestones, insisting upon the Diatomaceous cha- 

 racter of those innumerable microscopic disks of which Cos- 

 cinodiscuSy Campy lodiscus, and Actinocyclus are amongst 



* Published in vol. viii. of the ' Memoirs of the Literary and Philoso- 

 phical Society of Manchester' (1847). 



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