98 SPE^^CER : gneissoid granite in the Halifax hard bed coal. 
" grains of irregular outline, sometimes associated, and often joined, 
" as it were sewn together, by microcrystalline quartz, which also 
" occasionally extends into small patches. Numerous small inclosures 
" give it a dusty look ; many are empty cavities ; some contain fluid. 
" The felspar also occurs in grains of roundish to rather irregular 
" outline also often associated. It is much decomposed, but some is 
" probably orthoclase, and microcline can be distinctly recognized. 
" Parts occasionally are blackened by clustered granules. \Yithout 
" destroying the slide I cannot say whether these are iron oxide or 
some carbonaceous material which has infiltered. As its presence 
" has no important significance I have thought it needless to ascertain 
" its precise nature, but believe it probably of secondary origin. 
" Rather, roundish grains of quartz are occasionally included in the 
" felspar, as is common in old granitoid gneisses. 1 note a very little 
" flaky viridite. It is possible that the gneissoid structure is due to 
" mechanical deformation of a granite, but if so, reconsolidation has 
"been complete. The structure, in short, recalls a type of rock 
" which is exceedingly common among gneissoid rocks, which are 
" universally admitted to be much older than any part of the Cam- 
" brian, and which is, so far as my experience goes, exceedingly rare, 
" if not altogether wanting in any rock of Palaeozoic or later date." 
Considering the great interest attached to the discovery and 
examination of these boulders from coal seams, it may be important 
to point out some of the conditions attending the deposition of the 
strata enclosing the coal seam in which they occur, and also the 
general character of the strata, and the direction from whence they 
appear to have come. Dr. Sorby has well shown, by data derived 
from microscopic examination of the sandstones and grits of the lower 
part of the Coal Measures, that these rocks are composed of materials 
which were most probably derived from Scandinavia ; and this con- 
clusion is supported by the general trend of these strata, which is 
from north-east to south-west. The Coal Measures were deposited 
in a slowly sinking area, with occasional pauses or even slight 
elevations of the land above the sea level. The strata enclosing 
the Hard Bed Coal furnishes one of the most striking examples of 
these mutations of land and sea. A short distance below this coal 
