466 Reviews and Notices oj Books, 



in all the forms become larger as they recede from the centre 

 to the periphery, and again become smaller, on the lower side, in 

 the globose forms. Cells cylindrical, contracted below the aper- 

 ture, and thickened or expanded above, with rhomboidal openings 

 at each extremity. On one side the openings sometimes shows 

 obsolescent rays ; the interior walls of the cells are often striated 

 as if preserving the remains of transverse septa. 



In all these bodies the cells are arranged on curving lines which 

 diverge from the centre in a constantly enlarging circle ; these 

 are crossed by similar lines in an opposite direction, which thus 

 leave quadrangular or rhomboidal spaces, " like the engine turned 

 ornament of a watch." The form of these apertures' depends up- 

 on the degree of curvature, or upon the form of the mass to 

 which the curvature of the cell lines vnll conform. In all cases, 

 however, the cell is cylindrical beneath the exterior. 



Since the cells vary in size at different distances from the centre, 

 the size of the cells in separate fragments, affords no means, alone, 

 for specific determination. 



Regarding the form and mode of growth, I have recognised 

 the following species in the Galena limestone of the lead region. 



The species described are 



Receptaculites Oweni. 

 " lowensis. 



" fungosum. 



" glohulare. 



" infundibulum. 



•' hemisphericum. 



The first of these species sometimes attains to a diameter of 12 

 inches ; and if as Salter supposes, these fossils really belong to 

 Foramenifera, the present observations of Prof. Hall extend in 

 a remarkable manner our ideas of the development and number of 

 these singular creatures in the silurian seas. 



Prof. Hall states in the introduction of the report, that large 

 materials have been collected for extended publication on the 

 geology, palaeontology, and useful minerals of Wisconsin. We 

 hope that these will be speedily published, and in a manner 

 creditable to the State, and worthy of the talent and skill em- 

 ployed in the work. 



' J. w. D. 



