Oct., 1892. midland union of natural history societies. 223 
Not the least interesting or remarkable feature of the 
evening’s pleasure was a series of lantern slides, painted 
and exhibited by Mr. H. M. J. Underhill, of Oxford. These 
illustrated in the most beautiful and striking manner the life 
of our ponds and rivers. Many exquisite specimens were thus 
shown of the highly organised Rotifera, including several 
unnamed varieties, and also examples of the Amoeba and 
Vorticella, and other Infusoria. The interest of this beautiful 
exhibition was greatly increased by the lucid explanation of 
each slide given by the exhibitor himself. 
The varied programme of the evening was brought to 
a close by a hearty vote of thanks on behalf of the Union to 
Colonel and Mrs. Barnes for their most kind hospitality in 
affording to its members such a pleasant and memorable 
evening. 
GEOLOGICAL EXCURSION, August 24th, 1892. 
The neighbourhood of Oswestry is an extremely interesting 
one for the geologist, on account of the great diversity of the 
strata to be found over a very limited area. Thus, com- 
mencing at Tedsmore, six miles S.E. of Oswestry, there is 
an outlying portion of the Keuper marls and Waterstones, and 
in the course of nine miles all the intervening strata are repre¬ 
sented down to the Carboniferous Limestone. Oswestrv itself 
V 
is on the Permian, and between this and Tedsmore, the three 
divisions of the Bunter occur, viz., Upper Mottled Sandstone, 
Bunter Conglomerate (corresponding to the Pebble Beds of 
Warwickshire, etc.), and the Lower Mottled Sandstone. 
The study of the various strata is, however, rendered diffi¬ 
cult by the depth of the glacial sands and gravels which 
cover them. To the W.N.W. of Oswestry, in the course of 
the excursion, the three divisions of the Carboniferous strata, 
two or three of the Ordovician, and two of the Silurian (or 
“ Salopian ”) are to be seen. The Old Red Sandstone is 
missing in the neighbourhood visited (although it occurs four 
miles north of Chirk). The Carboniferous Limestone is to be 
seen lying unconformably on the Ordovician Shales, near 
Oswestry, and on the Wenlock Shale, near Chirk. An 
unconformity may also be seen at Llansantffraid between the 
Ordovician (Bala Limestone, etc.) and the Salopian (Llan¬ 
dovery) Shale which underlies the grits. 
Shortly after nine a.m. a start was made from the 
Wynnstay Arms Hotel, Oswestry, by the first detachment of 
the party, to the number of twenty-five or so, with every 
promise of a most interesting and enjoyable excursion—a 
promise which was to be fully realised, for the weather was 
all that could be desired except for a slight haziness of the 
