752 EEPORT — 1900. 



a great number of xenoliths of it, whicli through the acid magma have undergone 

 great alterations. 



3. The granophyre has ahsorhed a considerable quantity of the basic material, 

 thereby altering its own composition and effecting the crystallisation of hornblende 

 and mica, two constituents which we have to consider as not belonging to the 

 original granophyre magma. 



4. In the solidification of the granophyre two stages can be distinguislied, the 

 first giving rise to the formation of the rectangular orthoclase crystals, whicli 

 crystallised in parallel intergrowth with the plagioclase-xenocrysts, the second 

 forming a kind of groundmass in which fresh quartz crystallised, while the ortho- 

 clase filled up the remaining spaces. 



Interim Report on the Present State of our Knowledge of the Structure 



oj Crystals. 



Report on Life Zones in British Carboniferous Rocks. 

 See Reports, p. 340. 



TUESDAY, SEPTEMBER U. 



The following Papers and Eeports were read :— 



1, On Naiadita /rom the Upper Rhceiic (Bed K of Wilson's Section) of 

 Redland, near Bristol. By Igebna B. J. Sollas, B.Sc. 



The plant remains known as Naiadita are found in Rhsetic beds in the Severn 

 district below the Avon. Phillips mentions their occurrence at Tewkesbury, 

 Westbury-on-Severn, and Bristol. 



These fossils are well known from the description published fifty years ago by 

 Buckman. It was Buckman who chose for them the name Naiadita, because ho 

 considered them to be monocotyledonous plants resembling the members of the 

 order Naiadace£e. 



Mr. Starkie Gardner in 1886 re-examined them, and pointed out that the 

 markings taken by Buckman as having been left by the rectangular venation of a 

 Naias-like leaf were in reality fossilised cell-walls. 



Mr. Gardner concludes that the plant is a moss, and probably closely allied to 

 the genus Fontinalis. He speaks of a capsule, but of this he gives no description. 



A slab from the Naiadites bed of Pyll Hill, Bristol, was recently sent by 

 Mr. Wickes of that town to my father for examination, because it contains bodies 

 which were thought to be possibly gemmules of sponges. On this proving not to 

 be the case the specimen was handed over to me. 



The plant, which was delicate, slender, and moss-like in habit, is preserved in a 

 more or less fragmentary condition. 1 believe, however, that the parts are suf- 

 ficiently connected to show that the sporangia are situated at the bases of the leaves, 

 between their upper surfaces and the stem. The stems branch laterally, and a 

 sporangium is often to be seen near a point of branching. 



The shapes of the leaves are various, and this has led Buckman to establish 

 three distinct species. No doubt there may be more than one species present, but 

 certainly leaves of at least two difi'erent shapes are to be seen attached to one and 

 the same piece of stem, viz., small obovate leaves and larger ones of an elongate 

 elliptical shape. 



The epidermal cell-walls are preserved and their outlines are very clear. The 

 cells are long and rectangular, fchorteuing towards the bases of the leaves. No 

 stbmata are to be seep. 



