44 Reports and Proceedings. 
rostris, it is not certain that the latter is truly fossil; nor, if it be 
so, have we any knowledge of its stratigraphical position. 
3. Of the certainly fossil Ziphit, the stratigraphical position of 
Belemnoziphius longirostris is unknown; but all the other species 
of that genus, and Choneziphius planirostris, are derived from the 
English or Antwerp Crag, and are not known to occur out of it. 
4. So that at present we are justified in regarding Belemnoziphius 
and Choneziphius as true Crag Mammals. 
The following communications were read, June 8, 1864 :— 
1. ‘On the Rhetic Beds and White Lias of Western and Central 
Somerset, and on the discovery of a new Fossil Mammal in the Grey 
Marlstones beneath the Bone-bed. By W. Boyd Dawkins, Esq., 
B.A., F.G.S. 
After describing the sections in the district, and showing the 
paleontological relations of the White Lias to the Avicula contorta 
series and the zone of Ammonites planorbis, the author enunciated 
the following conclusions:—(1) That the true position of the White 
Lias is immediately above the Avicula contorta zone of Dr. Wright, 
and at the base of the Lower Lias shales ; (2) that it is entirely 
distinct from the Rheetic beds, lithologically and palzontclogically ; 
and (3) from the discovery of Rheetic fossils in the Grey Marls 
below the Bone-bed, that the latter belong to the Rheetic formation. 
He then proceeded to describe a two-fanged mammalian tooth, which 
he had found in the Grey Marlstones below the Bone-bed, and 
which he considered to be the analogue of the trenchant four- 
ridged premolar of Hypsiprymnus, of the section to which H. Hun- 
tert belongs. Until additional remains be found, its affinities to 
Microlestes or to Plagiaulax cannot be determined ; Mr. Dawkins 
has, therefore, named it provisionally Hypsiprymnopsis Rheticus. In 
conclusion he traced the range of the Marsupials in space and time, 
showing that of the six families into which Van der Hoeven divides 
the existing Marsupials, two—the entomophagous and sarcophagous 
Dasyurina, and the phytophagous Macropoda —had been repre- 
sented in England during the interval between the deposition of the 
Rheetic Marlstones and that of the Purbeck beds. 
2. ‘On the Geological Structure of the Malvern Hills and ad- 
jacent District.’ By Harvey B. Holl, M.D., F.G.S. 
The geological structure of these hills was described in detail, and 
it was concluded that the rocks hitherto treated of as syenite, and 
supposed to form the axis of the range, are in reality of metamorphic 
origin, consisting of gneiss (both micaceous and hornblendic), mica- 
schist, hornblende-schist, &c., all invaded by veins of granite and 
trap-rocks. It was then shown that the Hollybush Sandstone is the 
equivalent of the Middle Lingula-flags, and that the overlying black 
shales correspond with the Upper Lingula-beds, the whole being 
overlain, as in Wales, by Dictyonema-shales. These rocks, on the 
east of the Herefordshire Beacon, are altered by trap-dykes, which 
were shown to be of later date than those traversing the crystalline 
rocks before alluded to. Allusion was next made to the Upper 
