234 Correspondence. 
are also some beds which may turn out to be altered limestones; and 
then, this group is really an old mountain-chain, having an anticlinal 
jine, which (if the beds had not been broken through and broken up 
at the same time) would have given a ridge of many thousand feet 
high. These features, I think, distinguish this group of rocks from 
the Cambrians of Wales. 
JAMES PLANT. 
To the Editor of the GEOLOGICAL MAGAZINE. 
Sir,—In your last Number, under the head of ‘ Proceedings of 
the Glasgow Geological Society, a paper is reported to have been 
read ‘On the Discovery of Lower Carboniferous Fossils in the 
Upper Coal-measures ;’ and it is stated that they were discovered 
‘higher in the Carboniferous series than previously known.’ 
I beg to state that this is not the first discovery of marine forms 
in the Upper Coal-measures. They were discovered, several years 
ago, by Messrs. Hull and Green, of the Geological Survey, at 
Ashton-under-Lyne, in Upper Measures. Shortly afterwards, I had 
the good fortune to discover them in the upper part of ‘the North 
Staffordshire Coal-field.—I am, &c. JoHN WARD. 
25, STAFFORD STREET, LoNGTON, 
STAFFORDSHIRE. 
To the Editor of the GEOLOGICAL MAGAZINE. 
Sir,—I enclose some samples of a mineral I discovered about a 
year ago in some clay-land I have near the Humber-side at this 
place. I had a quantity of the clay dug, with a view of finding out 
what fossils it contained at a lower depth than it is common to dig 
it out for the purpose of making bricks. The clay at the surface is 
brownish in colour, but gradually becomes blue as you go lower, and 
at about ten feet deep is nearly black, very ‘sludgy,’ and apparently 
contains a great deal of vegetable matter. At about seven or eight 
feet I took a lump of the clay, and, kneading it in my hand, felt 
something prick me: I found what looked like small twigs, of from 
half an inch to an inch long, and varying from about the thickness of 
an average pin, to three or four times that thickness—but evidently 
iron or metal of some kind. I tried it with the magnet, and found 
it flew to it at once. JI have since found that it is itself magnetic, 
and that when slightly filed it will attract small steel filings. I 
showed a sample of it to Dr. Percy several months ago; and I under- 
stood him to say that the ‘structure’ was new to him, but that he 
would make some enquiry about it ; but as I have heard nothing 
from him on‘the subject, | presume he has forgotten all about the 
matter. I have therefore thought it my best plan to write this letter 
to you, thinking that either yourself or some of yourmany readers and 
contributors may perhaps kindly favour me by saying whether it is 
usual to find in such a place such a mineral.—I remain, &c., 
ALFRED Henry PECHELL, Barrister-at-law. 
Bsrron-on-Humper: Feb, 18, 1865. . 
