a new Carhoniferous Foraminifer. ' 179 



coloured limestone, the freshly fractured surface of which 

 appears almost homogeneous and sometimes subcrystalline 

 It is however, readily acted upon by the atmosphere ; and the 

 weathered portions reveal a spheroidal structure that inio-ht at 

 tlie hrst glance be assigned to purely physical causes depending 

 on some peculiarity in the mode of deposit. A fair idea of the 

 cliaracters of the rock forming this bed may be gained from 

 ilate Ail. hg 1, which represents an average specimen, with 

 the upper sm-face considerably weathered. Very frequently 

 the disintegration, instead of being merely superficial as in 

 the figured specimen, extends to a considerable depth, leaving 

 the stone m the condition of a crumbling mass of spheres. A 

 layer m this state exists between the surface-soil and the hard 

 rock ; and by a little treatment the fossil portions may be ob- 

 tained from It quite clear of the matrix. 



A few feet below this bed (in the same section), and sepa- 

 rated from It by a thin layer of shale and a stratum of lime- 

 stone containing Bryozoa, is a second and more considerable 

 bed, with tlie same sort of fusiform bodies distributed through 

 Its entire length and thickness. The individual specimens 

 are larger than those occurring in the later deposit, but they 

 do not constitute nearly so considerable a proportion of the 

 entire rock. The segments do not appear to differ in structural 

 characters from those found in the upper bed. 



Mr. Topley, of the Geological Sm-vey, has furnished me 

 witli a rock specimen from another section in the neighbour- 

 hood ot_ Elfhills, but at some distance from the main quarry. 

 The point from which it was taken is apparently about six- 

 teen feet higher in the series than the top of the quarry • but 

 not improbably it is only the upper bed, faulted : it imme- 

 diately overlies one of the branches of the whin-sill, and seems 

 to have been a good deal altered by heat ; but portions at least 

 of it are entirely composed of the same fossil remains. 



The Elfhills bed appears again on the banks of the Wans- 

 beck above Wallington Hall, where it has more or less of the 

 same spheroidal stiiicture, determined by the presence of its 

 characteristic fossil. 



xls the '' four-fathom limestone " traverses the Alston-3Ioor 

 district, It can scarcely be doubted that the specimens orio-i- 

 nally found by Mr. Charles Moore amongst other ForamiSi- 

 fera, associated with the mineral veins of the higher part of 

 Weardale, have been derived from it ; but hitherto no fossil 

 similar m character to those of the Northumbrian bed has 

 been ^discovered, though carefully sought for by my friend 

 Dr. Savage, of Nenthead, who is thoroughly conversant witli 

 the geology of that region. 



13* 



