Sep., 1891. 
REPORTS OF SOCIETIES. 
215 
is represented as a mass of altered Caradoc sandstone, with a lump of 
“greenstone” intruded somewhere near the middle, the metamorphism 
of the sandstone being presumably attributed to the presence of the 
igneous rock. On the east of the hill, in the main street of the village, 
there crops out a greenish sandstone, which the survey regarded as the 
unaltered Caradoc. This reading of the local geology has the merit 
of simplicity, but it is demonstrably erroneous in every particular. 
The intrusive greenstone and the altered sandstone do not exist, and 
the unaltered sandstone in the village is not of Caradoc age. Recent 
researches have shown that the supposed Caradoc sandstone is of 
Cambrian age, while the hill itself chiefly consists of volcanic ashes 
and flows of lava which were once ejected at the surface in the manner 
of modern eruptions, and these interesting rocks, so far from being 
younger than the Caradoc epoch, are really older than the Cambrian. 
I have, therefore, the pleasure of introducing to the club the oldest 
volcanic formation that has yet been detected in the earth’s crust, a 
formation which dates back to an epoch anterior to the deposit of the 
ancient strata in which the oldest known fossils have been discovered. 
The famous Eozoon canadense, the so-called Dawn-Animal of Sir Wm. 
Dawson, is indeed of greater antiquity than this great volcanic system ; 
but, as I regard Eozoon as one of the Mrs. Harrises of geological 
science, I do not take it into account. It was necessary to prove (1) 
that the green sandstone in the village was of Cambrian age, and (2) 
that the volcanic rocks are of greater antiquity. These points are 
more clearly shown in the Wrekin and at Caer Caradoc. In those 
localities the sandstone contains Lower Cambrian fossils and is under¬ 
lain by a band of quartz-rock, which rests transgressively upon the 
upturned edges of the lavas and ashes, and furthermore contains in 
abundance well-rounded pebbles of the lava. The discordance between 
the two formations is also well seen at Lilleshall, the green sandstone 
dipping to the south-east, while the volcanic strata have a dip to north 
or a little west of north. The volcanic rocks are therefore older than 
the Cambrian sandstone, and older by an interval. I am disposed to 
regard that interval as a rather wide one. These lavas and ashes are 
most fully displayed at the Wrekin and in the hills to the east of 
Church Stretton. They are of enormous thickness ; but as no base or 
summit to the series is known, no estimate can be offered. As the 
typical sections occur in the Wrekin, I have proposed for this great 
volcanic system the name of Uriconian. These results have been long 
admitted by students of the old rocks. The most recent convert to the 
new views is Sir Archibald Geikie, Director-General of the Geological 
Survey, who, in his presidential address to the Geological Society in 
February last, gives an outline of the evidence, and adopts the term 
“ Uriconian ” for the new system.—Mr. Edward Jones, of Granville 
Lodge, St. George’s, made some interesting remarks on the 
formation of the Coalbrookdale Coalfield, in the course of which 
he said: Twenty-five years ago I read a paper touching upon the 
working of the limeworks, &c., in that district. I may here 
observe that the original Government Geological Survey of the 
district is not very accurate, and the faults marked wide of the 
lines as they practically exist. The champion fault running through 
the heads of the coalfield is called the Lightmoor fault. It takes its 
rise at Lincoln Hill, near Coalbrookdale, runs through Lightmoor, 
under Malinslee and Priorslee Churches, and 200 yards east of St. 
George’s Church, 150 yards east of Muxton Bridge, and was supposed 
and delineated to run 500 yards east of Lilleshall Church ; but subse¬ 
quent workings have proved that the fault was through the hill, and 
