EXCURSION TO FROGHALL, CALDON LOW, AND ALTON. 249 
slope of Bunter Pebble Beds on either hand, with strips of the sombre 
crimson, but mostly mossy and variegated, conglomerate peeping here 
aud there from between the clustering ferns and wild flowers and 
foliage that almost clothe them; while above, rising abruptly into a 
perpendicular craggy cliff from the top of the Bunter slopes, could be 
seen the massive white and pink sandstone of the Lower Keuper, like 
a thick bed of basalt, capping the hills all round. 
We alighted a little after nine at the Froghall Station, where we 
were met by Mr. Fraser, the manager of the Caldon limeworks, and, 
haying refreshed, we walked on to the wharf, about half a mile 
distant, along a valley formed by the junction of a small stream 
descending from the limestone country to the north with the 
Churnet. We had left the terraced hills of the Triassic Rocks, 
and were now fairly on the Lower Coal Measures or Gannister 
Rocks, which in our front, over to the north and west, rose into 
bold dimpled hills crowned with thick tufts of pine, rather characteristic 
of the Lower Coal Measures. Beyond lay the picturesque Millstone 
Grit, rising sharply from the almost:featureless Yoredales, while 
perhaps the Carboniferous Limestone of the Weaver Hills formed the 
shadows which filled the background. The Cheadle coalfield, across the 
eastern edge of which our path lay, is about 1,000ft. thick, and forms 
one of those “basins” into which the Coal Measures of North Stafford- 
shire have been thrown on the west, called the Goyt Trough. 
The ironstone, for which the Gannister Rocks at Froghall have long 
been famous, was stored at the wharf in banks about 20ft. high, broken 
up into slabs, and separated into different qualities ready for transit to 
the smelting furnace. The hematite is of the usual dark-brown or 
blackish colour, being streaked with light-brown along the planes of 
bedding, giving it somewhat of a stratified appearance, the joints being 
mostly filled with calcite.* Some geodes in this ironstone yielded very 
minute six-sided prisms of calespar. The ironstone is usually found 
associated with dark, chocolate-coloured shales, and rests on from Ift. to 
14ft. of gray orreddish slaty clay, forming the lewest bed of the Gannister 
series in this district. It varies in thickness from lin. to22in. Aremark- 
able feature connected with this ironstone is that it is only found 
developed in what seem to have originally been “basins,” between 
saddles or folds of the already crumpled Millstone Grit; for over the 
more elevated underground ridges of the grit it is found to be represented 
by a mere trace of reddish ochre. The shales below it present similar 
phenomena. 
Froghall is also the terminus of the tramway from the Caldon Low 
limestone quarries, and here was the machinery for crushing the stone 
* An analysis of this ore, given in ‘‘ The Iron Ores of North Staffordshire,” shows 
that this hematite consists of :— 
IRETOSANO OF INON «|. cjcewice scr 52°83 Sulphuric acid! c.5. 2.0. c0ce 
Protoxide of manganese.... 0'81 Silicate see a aie ce 
ILA Cpa DOR GE Ose COOrEnS 14°61 WSET SA wants case 
WESSMESI A «5 <.:0:0sinivie's vies e.e'e.0 5 70 Organic matter... 5 
WATHODIC ACID wc ccciscccecsce 18:14 - 
Phosphoric acid ........+6.. 0°32 Total amount of iron...... 36°98 
