a a i a a es 
351 
thic materials of the granite, verified by analysis, have been 
so few, that I considered the Academy might not consider the 
present cases as unworthy of being placed on record in its Pro- 
ceedings. 
The analysis of these waters have placed in view another 
fact of much interest, in regard to the geognostic character of 
the granite of the Dublin mountains. In the waters there 
were found both potash and soda, but the latter in very great 
excess. ‘This indicates that the felspar of our Dublin granites 
is upon the whole a soda or albitic felspar granite, although 
in particular spots orthose or potash felspar may be found. 
This fact has been also verified by a great number of analyses 
of specimens of granites from various parts of the great mass 
which extends from Dublin into the County Wicklow. In all 
the analyses made, which included both ordinary granites and 
elyan or granite porphyries, both potash and soda were found 
present, and the latter almost always so preponderant as to lead 
to the conclusion that the potash should in most cases be con- 
sidered'to belong to the mica which the granite contained, and 
that the felspar was almost exclusively an albitic or soda 
felspar, containing only in some cases a small quantity of 
replacing potash. 
Dr. Apjohn made some remarks on the subject of Sir R. 
Kane’s paper, eliciting some further explanations from the 
author. 
Read, a letter from Mr. James S. Knowles, accompanying 
a donation of a cast of an inscribed monumental stone found 
lately in an excavation in St. Paul’s Churchyard, London. 
The stone, of the monumental portion of which the accom- 
panying cast is a fac-simile, was discovered in the process of 
excavating for the foundations of a new warehouse for Messrs. 
Cook, Sons, and Co., on the south side of St. Paul’s Church- 
_ yard, in the month of August, 1852. 
