74 
SCIENTIFIC NEWS. 
while globules of calcareous spar. The veins in the lime- 
stone, above and below this stratum, have rarely, if ever, 
broken through it, but rents proceed from these into the top 
and bottom of the toadstone, in which galena and the usual 
veinstones are sometimes found. 
Third Limestone. The most eastern basset of this rock, in 
the line of section, is on the western slope of Massen Low. 
Its average thickness near Matlock is about 80 yards. Its 
colour varies from grey to brownish black. It includes several 
beds of swinestone, with layers of dark grey modular chert. 
Its organic remains are numerous, and it abounds in mineral 
veins that afford galena, calamine,* and blende included in cal- 
careous spar and heavy spar. 
Second Toadstone. The most eastern basset of this rock is 
in Matlock high Tor. Its average thickness is about 80 yards. 
Its colour is yellowish or bluish grey. Some of its beds are 
magnesian limestone. Its principal organic remains are en- 
irochi. It contains metallic veins of galeva, calameric, and, 
it is said, of copper. 
First Toadstone. The first regular basset of this rock ap- 
pears to be in Matlock high Tor. Its average thickness is 
about 28 yards. Its general characters differ little from those 
of the third toadstone, except that it seems disposed in more 
regular beds or strata. 
First Limestone. The average thickness of this rock is 60 
yards. Its usual colour is lightish grey. Near the top it 
encloses beds of swinestone interlaid with dark or striped 
chert. The organic remains of this rock are anomia, entrochi, 
nautili, and other shells, together with many coralloids. It 
abounds in caverns and water swallows, and in numerous me- 
tallic rake veins, or long vertical rents. Massive fluor (Blue 
John) and elastic bitumen occur in this rock. 
The greator Limestone Shale. The average thickness of this 
rock is about 150 yards. Its general character is that of a 
black or dark brown shale, inclosing beds of a soft yellowish 
sandstone, and of a dark blue limestone : also thin beds of 
clay, iron, stone, and septaria. Its organic remains are not 
numerous, consisting chiefly of anomia, mya, helices, and a 
few vegetable impressions. 
First 
