726 PROCEEDINGS OF THE SOCIETY. 



external forms of plants and a study of their internal structure. Those 

 fossil remains of plants with which the casual observer was most 

 . familiar, showed little or nothing of their internal structure, and it was 

 only when we came to the petrified remains, where the plants had their 

 tissues thoroughly impregnated with lime or other mineral matter, that 

 the structure could be studied. Broadly speaking, specimens exhibiting 

 external form showed no structure, and vice versa. Most of the British 

 coal-measure material which was of value in these investigations occurred 

 in the form of calcareous nodules imbedded in certain mines in the coal 

 itself ; these concretions were simply crammed with vegetable remains 

 which had been prevented by petrifaction from becoming reduced to 

 coal. In the French Carboniferous deposits the preserving agent had 

 for the most part been silica. 



Dr. Scott then proceeded to demonstrate the structure of some 

 Carboniferous plants by the exhibition of a fine series of photographs 

 shown on the screen by the Epidiascope, first showing, in each family 

 dealt with, some examples of external habit, and then going on to sec- 

 tions exhibiting the internal structure. The first group taken was the 

 Calamariese, which have much in common with the modern Horse-tails. 

 In sections of the cones the spores were well seen in the sporangia. 

 The heterosporous nature of the fructification was pointed out in some 

 examples, from which and from various other points in their organisation 

 it was concluded that these plants attained a higher grade of differen- 

 tiation than their present representatives. The series further included 

 examples of stems and cones of the Sphenophylleae, a group in some 

 respects intermediate between Horse-tails and Clubmosses ; also of the 

 Palaeozoic LycopodiaceaD (Lepidodendron and Bothrodendron), in which 

 the cell-structure and details of the fructification were remarkably well 

 shown. He also exhibited under a number of Microscopes on the table 

 many of the actual sections, from some of which the lantern photo- 

 graphs had been taken, and mentioned that the chief difficulty he had 

 experienced in the matter was in making a selection from the large 

 amount of material available. He had purposely limited himself to a 

 few groups of Palaeozoic plants. 



The President said he was sure it would be unnecessary, after the 

 way in which they had received Dr. Scott's communication, to ask if 

 they desired to thank him for it. He (Dr. Scott) had very wisely given 

 them an account of two extinct types of fossil plants, in which the ex- 

 ternal form and the internal structure, both of which had been preserved in 

 a fossil state, had been shown on the screen and explained, and it would 

 no doubt be the opinion of the Meeting that this had been done in a 

 very complete manner by the author. A point which was of great 

 interest to them was that the specimens they had been looking at were 

 the actual sections of fossil plants, and not things which were what 

 was called " faked up " ; and therefore they could not fail to afford the 

 greatest interest. He was quite sure that Dr. Scott could give them a 

 dozen evenings of this kind, as there were many other formations beside 

 the coal measures in which the microscopic structure of plants has been 

 met with, all of which were very familiar to him. He desired to con- 

 vey, on behalf of the Fellows of the Society, their very best thanks 

 to Dr. Scott for his interesting and instructive demonstration. 



