104 GLEANINGS—REPORTS. 
New Geronocican Formarions.—Dr. Henry Hicks now recognises 
three formations in Wales of earlier date than the Cambrian rocks. 
The beds which form them were mapped by the Geological Survey, either 
as igneous, or as altered Cambrian or Silurian rocks. In Pembrokeshire 
he distinguishes beneath the Harlech (Cambrian) group amass of voleanic 
breccias and ashy schists and slates, perhaps 8,000ft. thick, on which the 
Cambrian beds repose unconformably. For this series Dr. Hicks proposes 
the name Pebidian from Pebidiauc, the name of the division or hundred 
in which these rocks are mainly exposed. They in their turn rest uncon- 
formably on compact quartz schists, chloritic schists, and indurated 
shales with beds of dolomitic limestone. The base of these beds is not 
seen, but they have a very high dip, and the thickness exposed is esti- 
mated at 15,000ft. Dr. Hicks has named them Dimetian from Dimetia, 
the ancient name for a kingdom which included this part of Wales. In 
1877 the presence of both these series of rocks was proved in Caernar- 
voushire, in North Wales, and at the last meeting of the Geological 
Society, (Feb. 5th, 1879,) Dr. Hicks stated that he had ascertained the 
presence of a third new group of pre-Cambrian rocks, which forms ridges 
of quartz-felsite in the neighbourhood of Haverfordwest. They lie 
between the Dimetian and the Pebidian rocks, and he proposed to name 
them Arvonian. Of course these names are only proposed provisionally, 
and as a matter of convenience ; but there can be little doubt that the 
great advances made in late years in the study of igneous and 
metamorphic rocks, together with the introduction of the use of the 
microscope, will greatly alter our ideas of the nature of many of these old 
rocks, and will render their thorough re-examination a matter of necessity. 
MIDLAND UNION OF NATURAL HISTORY SOCIETIES. 
Tur Srconp AnnuaL Mretina or Members will be held at Leicester, 
on Tuesday and Wednesday, May 20th and 21st. A circular will shortly 
be issued to all members of Societies in connection with the Union, con- 
taining the full programme of this Re-union of Midland Scientists and 
their friends. The members of the Leicester Literary and Philo- 
sophical Society are working ‘hard to make the meeting a success, 
and the Mayor of Leicester has kindly granted the use of the new 
Municipal Buildings, The Excursion to Charnwood Forest on the second 
day, (May 21st,) itis proposed to divide into two parties, one mainly 
Geological, and the other mainly Botanical, so as to avoid the incon- 
venience arising from the presence of such a large number in a single 
party as would render it unwieldy and unmanageable. Full particulars 
of the proceedings proposed for both days will be published in the May 
number of the ‘ Midland Naturalist.”—-Hpwarp W. Bapveer, W. JEROME 
Harrison, Hon. Secs. to the Council.—Birmingham, March 24th, 1879. 
Aeports of Sorieties, 
BIRMINGHAM NATURAL HISTORY AND MICROSCOPICAL 
SOCIETY.—February 25th.—Gronocican Srcrion.—Mr. W. Southall was 
elected President of the Section.—Mr. T. H. Waller read some notes on “ Fluid 
Cavities, and other Inclosures in Crystals,” giving a short sketch of their general 
characteristics, and of the method in which they have been produced, with some 
of the deductions which have been drawn from observations made on them. 
Specimens illustrating various points in the paper were exhibited, and a section 
of obsidian from Mexico, showing a polarising structure. produced by the 
straining of the glass round some of the included felspar crystals. March 4th— 
GenrerAL Mretinec.—Mr. Thos. Bolton exhibited embryos of trout and salmon, 
and young Plumatella repens and Fredericella sultana, emerging from the stato- 
blasts.—Mr. J. E. Bagnall exhibited three mosses—Fissidens exilis, from Knowle, 
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