145 



what was their exact form, because they are variously altered by the 

 pressure to which they have been subjected, but probably they have been 

 nearly splierical and attached by a sort of umbilicus, the point of attach- 

 ment of which is easily seen on some of them. It is impossible to 

 believe that these bodies have been preserved under the same 

 conditions as those which have given to the other specimens all the 

 appearance of ordinary combustion, because the active heat necessary 

 to produce such an appearance upon common vegetable tissue would 

 equally act upon the sporangia, and destroy all traces of vegetable 

 structure. 



Anthracite coal evidences another mode of carbonization than those 

 which 1 have hinted at, perhaps differing in degree only from the 

 process by which ordinary coal is formed ; but its structure and history 

 is a most desirable subject for enquiry, of a more searching and philo- 

 sophical character than has yet been bestowed upon it. 



I have only further to call attention to a singular impression in a 

 piece of what appears to be Torbane-hill coal. It is a most remarkable 

 object. It is a slight depressed form, which at first sight suggests an 

 animal or vegetable scale, broad-pointed like a lancet at one end, and 

 irregular and fibrous-looking at its base, as if it had been violently 

 detached from some surface. It seems made up of concentric ridges, 

 equi-distant from each other, and from the edge, these being connected 

 by close transverse striae or ridges. At first I thought it might be the 

 bud of some plant, but, after long and careful examination, I have been 

 unable to come to any satisfactory opinion upon this question ; but I 

 have laid it before the the Society in the hope of receiving the 

 suggestions of others. 



THIRTEENTH ORDINARY MEETING, 



Held at the Royal Institution, on the 4th May, 1857, 



THOMAS INMAN, Esq., M.D,, Tresident, in the Chair. 



The following were elected Ordinary Members : — 

 John D. Cleaton, 

 Rev. CiiARi.Es H. Burton, M.A. 

 The President read a letter from Samuel H. Thompson, Esq , of 

 Thingwall-hall, communicating a valuable donation of books from the 



