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VI.—A Catalogue of the Fossils of the Permian System of the 
Counties of Northumberland and Durham, drawn up at the 
request of the Tyneside Naturalists’ Field Club. By Ricuarp 
Tlowse. 
Tus earliest notices of the fossil remains of the Magnesian-lime- 
stone of this district are those made by Mr. N. J. Winch, in a 
paper entitled “ Observations on the Geology of Northumberland 
and Durham,” published in the Geological Transactions, Ist ser., 
Vol. IV. In this paper nine species only are mentioned as oc- 
curring in the Magnesian-limestone of the neighbourhood of 
Sunderland. As they are rather vaguely described, it is very 
difficult to say what species are intended. About the same time 
that Mr. Winch’s paper was read before the Geological Society, 
several less important communications, on the same subject, 
were made to the Annals of Philosophy, and the Philosohical Ma- 
gazine. ‘Ten years later, Professor Sedgwick gave a much longer 
list of these fossils,in his valuable paper “On the geological 
relations and internal structure cf the Magnesian-limestone,” 
etc, in the Geological Transactions, 2nd ser., Vol. III.— 
More than thirty species from our district are included in this 
list, but, unfortunately, some of them are so slightly noticed that 
the species cannot now be recognised. The last and by far the 
most complete list, is the one given in the Geology of Russia. 
The fifty-eight species mentioned in it from the Magnesian-lime- 
stone of Northumberland and Durham are included in the tabu- 
lar list of the Fauna of the Permian System of Europe, and form 
about one-third of the total number of species peculiar to these 
rocks. Within the last few years, additional species have been 
discovered in our limestone, some few of which have been before 
noticed in the equivalent rocks on the continent ; the others 
appear to be entirely new. 
The Permian System includes all those rocks which are situated 
between the Carboniferous and Triassic Systems. Its principal 
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