Reports & Proceedings — Geological Society of London. 329 



the Abbotsbury Iron-ore is placed as the second zone of the 

 Kirameridgian, and is correlated with the M arket-Easen Clays. The 

 Portlandian is divided into nine zones ; but the term as used in 

 the paper includes the Portland Oolites, Portland Sands, and Upper 

 Kinimeridge Claj' of English authors. 



Three new genera of Ammonites are named, and two new zonal 

 species of Ammonites are defined. 



2. "The Volcanic Pocks of the Forfarshire Coast and their 

 Associated Sediments." By Albert Jowett, M.Sc, F.G.S. 



The peculiar intermingling of fine sediments with the Lower Old 

 Red Sandstone lavas of Scotland is well known from the writings of 

 Sir Archibald Geikie. 



The author has found that in Forfarshire these sediments are 

 frequently amygdaloidal, the production of the cavities having been 

 accompanied by the buckling and fracturing of the layers of sediment. 

 It is suggested that such eflfects may result from the pouring of 

 molten rock over wet unconsolidated sediment : steam being produced 

 within the sediment, but unable to escape owing to the presence of 

 the overlying rock. The suiface of the sediment was apparently 

 ploughed up by the lava, the lower portion of which occasionally 

 contains rounded nodules of hard amygdaloidal sediment. The 

 sediment is sometimes slightly altered where in contact with the 

 volcanic rock. 



Further evidence of the pouring of molten rock into water is 

 furnished by the occurrence of a rude pillow-structure in some of 

 the lavas. 



Several lenticular conglomerates are interbedded with the volcanic 

 rocks, resting upon eroded surfaces of the latter. The conglomerates 

 consist of large rounded blocks of volcanic rock, enclosed in a matrix 

 composed almost entirely of volcanic debris. 



Most of the volcanic rocks are olivine-basalts, rhombic pyroxene 

 as well as olivine sometimes bein^: present. Some contain rhombic 

 pyroxene to the exclusion of olivine. A few porphyrite dykes of 

 Lower Old Red Sandstone age are intruded in the lavas. 



The fine sediments consist of a variable proportion of quartz and 

 mica and a little felspai', together with chloiite, iron oxides, and 

 occasional minute fragments of volcanic rock. 



Calcite, qiiartz, chalcedony, and chlorite are the commonest 

 minerals in the amygdules, in both lavas and sediments. 



In the south-west of Lunan Bay, a mass of Upper Old Red 

 Sandstone with a basal conglomerate has been found resting 

 unconformably upon the Lower Old Red Sandstone volcanic rocks. 



3. " On a group of Metamorphosed Sediments situate between 

 Machakos and Lake Magaii in British East Africa." By John 

 Parkinson, M.A., F.G.S. 



That part of British East Africa which borders the Athi Plains and 

 extends westwards to the eastern edge of the Rift Valley, is undulating 

 country composed of foliated rocks of ancient appearance, crossed by 

 pegmatites which are unconnected with anj'- apparent granitic 

 intrusions. 



