386 
THE GEOLOGIST. 
rocks. The discovery is all the more important that so few of the class have 
been found in any of the numerous localities of the Old Red — one or two in 
England, more abundantly in Russia, and even there of comparatively rare 
occurrence. One shell, however, the Atrypa reticularis^'' says the author of 
Siluria, " ranges even to the furthest known geographical limits of the Devo- 
nian rocks ; to Armenia, the Caucasus, and China on the east, and to the 
Devonian deposits of America on the west.*" 
I forwarded a small slab of the deposit to Mr. Salter, who has returned for 
answer, as the result of his examination, " Though very obscure, there cannot 
be much doubt of the bivalve shell being a Modiola or related genus ; but it is 
so imperfect that I should not like to say whether this very thin shell is a 
marine one or not. The same with the Entomostraca. They may be Ci/pris, 
but are quite as likely Cy there I may further mention that a shdl somewhat 
like is found in the Lower Old Red of Shropshire, accompanied by marine 
genera of Entomostraca. The species is probably new." This interesting 
fossiliferous slab is now placed in Jermyn-street Museum. 
There are, in addition to the above, several other forms of mollusca, one of 
which resembles the genus Atrypa, another is Uke the typical Spirifer, and 
some are so thin and broken as scarcely to present their true characteristics. 
They are, however, sufficiently numerous, and to be easily extracted from their 
soft marly matrix. Better specimens are therefore to be looked for, and probably 
also various new genera in a deposit otherwise so rich in organic forms of 
marine life. Some of the shells are smooth, and others deeply and beautifully 
striated. Some are so extremely filmy as to be almost detached by the breath, 
or break by a slight impression of the nail. 
The Entomostraca are exceedingly numerous, some microscopically 
minute, and others large enough to be examined by the naked eye. A oed of 
fully an inch thick is entirely composed of myiiads of these organisms, fre'Sh 
in colour, and perfect in outline and structure as when they sported in the 
waters and shallows of the Devonian seas. The mass is extremely friable and 
brittle, as consisting chiefly of these minute bodies themselves, and a soft cal- 
careous or aluminous matrix of a light bluish coloui'. Organisms of the same 
family are distributed up and down in the thirty feet of exposed rock, as if 
floating everywhere in the turbid water, they had dropped at random into the 
muddy silts. The richer portion is towards the base of the cliff, and consists 
almost exclusively of the creatures bodies themselves, agglutinated by a thin 
paste of calcareous shale. 
I shall now conclude with a few general "remarks, as serving to show the 
relations and theoretic value of this new fossil locality, and the bearings more 
especially upon our Scottish palaeontology, some recent northern conclusions of 
which may be thereby disturbed. 
1. Do these grey flagstones and indurated shales form part of the Devonian 
system, or true Scottish Old Red sandstone ? I have in my own mind nof the 
slightest doubt about the answer that must be given to the question. The 
other members of the series are all in the immediate vicinity ; and from Park- 
hill to Gleneagles — thirty miles in linear distance along the slope of the Ochil 
range — the grey and blue coloured tilestones can be distinctly traced through- 
out, feathering out and in among the traps and in various places exhibiting the 
same texture and marly character as the Dron deposit. At the same time it 
has to be stated that some regard this as the under Carboniferous series. Mr. 
Powrie, upon a short inspection, all but concluded that it was ; and in corro- 
boration of these views, I have to mention that pits in search of coal have been 
Biluria, 3rd edition, p. 297. 
