186 Reports & Proceedings— Edinhurgh Geological Society. 



except in its greater content of water. The minerals, however, are 

 mainly hornblende and analcite. 



Corresponding to the soda-series considered above, few leucite 

 rocks are known, the granitoid types so far recognized being restricted 

 to certain ejected blocks from the tuffs of Monte Somma. Puglianite 

 is mainly composed of leucite, anorthite, and augite, and is the 

 homologue of mareugite. A heteromorphic form of puglianite, 

 known as sebastianite, is mainly composed of biotite, anorthite, and 

 augite, and corresponds to mafraite in the soda series. 



The paper concludes with a series of thirty-three analyses, 

 including several which appear for the first time. 



Arthur Holmes. 



REPORTS AND PROCEEDINGS, 



Edinburgh Geological Society. 

 February 18, 1920.— Mr. E. B. Bailey, M.C., B.A., F.G.S., F.R.S.E., 

 President, in the chair. 



" On the Vascular Plants of the Chert Band of Rhynie, Aberdeen- 

 shire." By Dr. Kidston, LL.D., F.R.S., President of the Glasgow 

 Geological Society. 



The remains of four vascular plants have been discovered in the 

 silicified peat bed at Rhynie, Aberdeenshire. These are — Rhynia 

 7najor K. & L., R. Gwynne-V aughani K. & L., Hornea Lignieri 

 K. & L., and Asteroxylon Mackici K. & L. Though their remains 

 occur in more or less fragmentary condition, it has been possible, 

 in the case of the first three, to obtain an almost complete knowledge 

 of their morphology and anatomy. In regard to Asteroxylon Mackiei 

 the vegetative region is known with considerable fullness, but the 

 sporangia, which we believe to belong to this species, have not been 

 found in organic connexion with its stem or branches, so there is an 

 element of doubt on its fertile condition. All these vascular plants 

 appear to have grown in a gregarious manner. A brief description 

 of each may now be given. 



Rhynia major was rootless and had no leaves. It consisted of a 

 system of dichotomously branched cylindrical stems, which arose 

 from underground branched rhizomes, that were attached to the 

 peaty soil by numerous non-septate rhizoids. The plant was larger 

 than R. Gwynne-V aughani, and probably attained a height of 

 40-50 cm. There is, however, no clear information on this point. 



The rhizome is composed of delicate tissue with a vascular bundle 

 which dichotomized, and some of its branches grew upwards as 

 tapering aerial stems. The stem bore no leaves or lateral projections. 

 It consisted of a wide cortex composed of a narrow outer, and a 

 wide, more delicate, inner zone. The vascular system consisted of 

 a simple cylindrical stele, formed of a solid strand of tracheides, 

 with no distinction of protoxylem and metaxylem. Surrounding 

 the xylem was a broad zone of phloem. 



