234 Geological Society. 



air : and the union of heated titanic acid with nitrogen (forming a 

 nitride of the metal) takes place, indeed, with so much energj'^ as 

 to generate light and heat ; and thus constitutes a genuine case of 

 combustion, in which nitrogen, and not oxygen, acts as the sup- 

 porter. 



Although titanium is evidently present to some extent in most 

 volcanos, the author is not disposed to think that it abounds suffi- 

 ciently to account for the large quantities of sal ammoniac that are 

 known to occur ; but, rather, he argues by analogy that ])robably 

 not only titanium but other metals, such as iron, and probably even 

 hydrogen, may combine directly with nitrogen in the interior of 

 the globe, under conditions of great pressure and other circumstances 

 likely to modify the nature of those reactions which take place 

 under our eyes. 



In a postscript the author adverted to the recently discovered fact, 

 that boron, like titanium, has the property of combining directly 

 with the nitrogen of the air, and that the compound which it forms 

 with it also possesses the property of evolving ammonia under the 

 influence of the alkaline hydrates. 



2. "On the Granites of Ireland: Part II. The Granite of the 

 North-east of Ireland." By the Rev. Prof. S. Haughton, F.G.S. 



This communication was a continuation of the details of the 

 author's researches in the granites of Ireland. Part I. v.as pub- 

 lished in the r2th volume of the Journal. In this paper Mr. Haugh- 

 ton first treated of the potash-granites ; giving their analyses and 

 atomic quotients ; and, secondly, described the soda-granites in like 

 manner ; drawing the following conclusions from the examination : 

 — 1st, that both in Leinster and the County Down, the potash- 

 granites are more constant in composition, both mineralogical and 

 chemical, than the corresponding soda-granites ; Sndty, that the 

 potash-granites appear to be the standard tyj)e of granite, from 

 which other granites and crystalline rocks are formed (as more or less 

 overlying and superficial coatings) by the addition of bases ; for 

 example, the anorthite-syenite of Carlingford, the soda-granites of 

 Newry, and in Leinster the outlying patches of granite between the 

 main chain and the sea; Srdly, that the potash- granite of Leinster 

 is more persistent in external character than the potash-granites of 

 Newry, although the latter are equally constant in chemical com- 

 position. 



3. "On the Classification of the Palreozoic Strata of the State of 

 New York." By Dr. J. J. Bigsby, F.G.S. 



In the synoptical view of the strata and fossils of the palaeozoic 

 basin of New York, read before the Society Nov. 18, 1857, the author 

 desired to arrange tl:e vast stores of information contained in the 

 Official Reports of the State Geologists of New York in a methodi- 

 cal and accessible form ; and in the present communication he treats 

 succinctly of the stratigraphical arrangements hitherto used, and 

 the classification now adopted by himself. This was printed in the 

 abstract of the author's former paper (Phil. Mag. Jan. 1858, p. 76) : 

 it is but little modified from that proposed by De Verneuil ; and is 



