58 CARBONIFEROUS AND PERMIAN FORAMLMFERA. 



This somewhat important fossil formed the subject of a paper by myself in the 'Ann. 

 and Mag. Nat. Hist.' (Joe. cit.) about five years ago. A few separated segments col- 

 lected by Mr. Charles Moore, whilst engaged upon the fossils found in mineral 

 veins, had been sent to me a year or two previously with other microzoa for examina- 

 tion, but these were insufficient for accurate description, and the provisional name 

 Cartcria was given to them with the idea that they were chambers of an organism 

 belonging to a new type of Lituolce. The bed of limestone on Sir W. C. Trevelyan's 

 estate at Elfhills in Northumberland, which furnished the material for my paper, had been 

 known for many years, and its physical peculiarities had not passed unnoticed, but it 

 had not been submitted to microscopic examination, and had been generally regarded as 

 a pisolitic or concretional rock. The particular layer of the Four-fathom Limestone, cha- 

 racterised by the presence of Saccammina has for generations been known to the Alston 

 miners as the " spotted post." 



I was not aware till long after the paper referred to was published that the organism 

 had been previously recognised as a fossil, still less as a Foraminifer. I find, however, 

 by Mr. Bonnie's note in the ' Geological Magazine' for January, 1876, that Saccammina 

 had been collected by Mr. R. Gibbs as far back as the year 1858 or thereabouts, and 

 that the specimens were entered by the late Mr. Salter in the Jerniyn Street Catalogue of 

 Fossils, published in 1865 as " Foraminifera in Limestone; Cat Craig, Dunbar," though 

 without further particulars. 



My attention has also been called to Professor M'Coy's description in the year 1854, 

 of a Carboniferous fossil which he names " Nodosaria fusuKnaformis," collected in the 

 Parish of Shivey, Co. Tyrone, Ireland. The brief verbal description answers fairly to the 

 general characters of Saccammina as far as it goes, except in the statement that the organism 

 " agrees almost perfectly with d'Orbigny's Nodosaria rudis and N. ruyosa ;" but it appears 

 to me insufficient, in the absence of any assistance from figures, to identify the species. 

 I have endeavoured to obtain further information from the officials of the Irish 

 Geological Survey, and from other geologists likely to be acquainted with the subject, 

 but hitherto without result. Under these somewhat difficult circumstances I have 

 thought the course least open to objection and certainly that least likely to lead to con- 

 fusion would be to retain the name by which the fossil has become generally known 

 amongst geologists and palaeontologists. 



The characters of the Carboniferous Saccammina and its mode of occurrence will be 

 more satisfactorily gathered from the figures on PI. I than from any mere verbal 

 description. It is essentially a rock-builder; that is to say, whole beds of limestone of 

 large extent and considerable thickness appear to be chiefly, and in places entirely, 

 composed of its remains. The description originally given of its occurrence in the two 

 beds at Elfhills in Northumberland applies equally to rock specimens from other 

 localities, and may be repeated without material alteration. 



" The uppermost bed exposed in the Elfhills quarry appears to be entirely com- 



