ME. H. B. BRADY ON SACCAMMINA CARTERI. 269 



XI. — On Saccammina Carteri, a new Foraminifer from the Car- 

 boniferous Limestone of Northumberland. By Henry B. Brady, 

 F.L.S., F.G.S. (Plate XI.) 



Introductory. — Notwithstanding the prominent place occupied 

 by the Mountain Limestone amongst the geological formations 

 of Great Britain, its geographical extent and its enormous thick- 

 ness, but little is known of the Foraminifera of the earlier Car- 

 boniferous age. The organic remains of which the calcareous 

 beds are at times almost entirely composed afford abundant evi- 

 dence of their marine origin, and analogy with other limestone 

 strata would lead to the expectation that Foraminifera would 

 constitute an important part of their fossil fauna ; yet were a 

 catalogue drawn up representing the present state of our know- 

 ledge of Carboniferous Invertebrata, the whole of the subking- 

 dom Protozoa would be told off in a few lines. Nor have we 

 far to seek for the reason of our comparative ignorance of the 

 minuter fossils, indeed we need hardly look further than the 

 physical characters of the material forming the beds to see where 

 the difficulty lies. Our Mountain Limestone is almost always 

 exceedingly hard and compact, sometimes even subcrystalline, 

 and scarcely ever admits of examination in respect to its Mi- 

 crozoa otherwise than by means of transparent sections, which 

 yield but little reliable information. It is only here and there 

 that pieces can be met with soft enough to allow the separa- 

 tion of their constituent fossils by washing or other mechanical 

 means ; and the cases are still rarer in which any chemical pro- 

 cess can be resorted to with advantage to the same end. But 

 possibly an even greater difficulty exists in the Microzoa them- 

 selves. The Bhizopoda, at least, either from natural deficiency 

 of marked characters, the obliterating effects of time, or the al- 

 teration produced by the process of mineralization, present seri- 

 ous obstacles to accurate study. 



Under these circumstances, the discovery of Foraminifera of 

 a well-defined and easily understood type in the Carboniferous 

 Limestone is a matter of some importance, and an additional 



