392 
THE GEOLOGIST, 
in the outer eonecutric lanilnatccl layers of still uiiliardencd mud eneircliiig 
them. I can bring evidence to show tliat this is no ett'cct of disintegration ; 
and I am anxious to know how far the laws respecting chemical segregation 
under conditions sueii as described arc ascertained, or if any relation can be 
traced betw een such facts and the well-known phenomena of slaty cleavage — 
the twisting, as it were, of gneiss round the granitic centres of mountains, and 
the contortions in various rocks hitherto erroneously ascribed to violent squeez- 
ing, &c. The manner in which water enters and leaves a given substance may 
idtimately produce a change of form, just as eleetiic currents passed through 
iron render it different from its former state. I have observed that where tJie 
substance acted ujjon is a stationary mass of mud or sand, the layers all foUow 
one direction, until we come to a sort of axis, as it were, and there the direc- 
tion of the lamina; become reversed. 
Now if the eryst;dline arrangement of bodies depend upon the weight of 
their atoms, and that the medium in which they are placed, as well as the 
motions to which they are subjected must be studied to produce artificial crys- 
tals, wiiy should chemists not be able to elucidate the laws by which large 
masses not only have an internal minute crystalline structure, but also a regular 
geometric arrangement into larger squares or circles, both these effects being 
produced by the force of gravitation. Were it proved that the lamellar struc- 
ture of rocks owes its origin to water, it would be an additional evidence that 
granitic rocks are in reality not of igneous origin. — Yours, &c.. A., Belfast. 
Manufactuke of Stone Implements. — Sir, — Tlie stone axes such as your 
"Inquirer" describes having doubtless excited much interesting speculation, 
it is to be hoped your next number will contain replies to some of his queries 
regarding impleinents wliich seem to have been manufactured by people singu- 
larly endowed with the virtue called patience. Perhaps the author of the paper 
on the " Giant's Causeway," which appeared some time ago in your magazine, 
being an antiquarian as well as a geologist, would give some suggestions 
regarding their manufacture ? 
I have seen one, belonging to Lord Talbot de Malahide, the careful work- 
manship and high finish of which might well call forth similar inquiries to 
those of your correspondent. It was, as nearly as I can recollect, formed of 
basalt also ; and being so well finished suggested the use of a metal in its 
manufacture, which, however, may have been too scarce to have superseded the 
use of stone-weapons. 
Stones along a sea-beach are often perforated by marine creatures, so that 
handles could easily be adapted to them, but then they are always composed of 
limestone, a rock which I have never known to be used for these stone axes. — ■ 
A. B. W., F.G.S. Sept. 8th, 1860. 
Lias at Wiiitciiukcii. — Sir, — In the geological map that accompanies the 
last edition (the 3rd) of Sir R. Murchison's " Siluria" I observe a patch of 
Lias marked as occurring between Whitchurch and Market Drayton. 
I should be glad to know whether on that patch there be any accessible sec- 
tions whence might be procured specimens of the very interesting fossils of the 
Lias formation. Being a new comer to the neighbourhood, and moreover a 
very tyro in geological studies, I, on both these grounds, stand in need of a 
little help in the way of information. — Faithfully yours. Omega. 
P.S. Are there any geologists in this locality or neighbourhood ? 
Fish from the Coal-Measures. — Sir, — You will oblige me by informing 
rne in your next number which is the best work that treats of the fish of the 
Coal-measures next to Agassiz's " Poissons Possiles." — Subscriber. 
The fossil fish of the Carboniferous rocks are not yet fuUy described. 
Beyond some scattered notices by Egerton (in the Geol. Quart. Jour.) and 
others, there are no other descriptions except those in Agassiz's great work. 
