236 
THE GEOLOGIST. 
ing to the authors, none at all in the great beds of red sandstone ; hence 
the question, are all these beds jurassic, or does the red sandstone repre- 
sent an island of the Trias? The authors incline to tlie opinion that all 
the rocks between the dolomite and the Dobra are jurassic, including 
the Dobra limestone itself. If the Dobra limestone be jurassic, the authors 
contend that the eastern part, if not the wliole of the Cantabrian chain, 
which reach 2600 feet, are likewise jurassic ; and that the conclusion then 
is inevitable, that the jurassic formation extends into the province of the 
Asturias, and that the whole of the geology of the eastern part of that 
province requires rectification. 
After the geology, the third part of the book is devoted to the geognos- 
tical relations of the more important metalliferous deposits, and the fourth 
to the mineralogical structure and chemical composition of the ores, with 
some remarks upon their mode of production ; and finally, we have chap- 
ters on the deposit of sulphate of the soda in the valley of o arama, near 
Aranjuez ; on the cliemical composition of a lacustrine dolomitic lime- 
stone in the neighbourhood of Madrid ; and on some curious molecular 
changes produced in disilicate of zinc and some of its compounds with 
carbonates by the action of heat. This work is well worthy of the attention 
of geologists. 
Geoloffical Essays, and Sketch of the Geology of Manchester and the 
Neighbourhood. By John Taylor. London': Simpkin, Marshall, and 
Co. 1864. 
It is refreshing to take up a book on Geology in which we find ourselves 
free from the set phrases and pratings of the old school of geologists, or 
the hackneyed and tiresome inveighings against the hard words of science, 
so common in the multitude of works on so-called popular science. Of 
geological nomenclature, at least, Mr. Taylor takes a more sensible view 
than most of his "popular" contemporaries, and he at least considers geo- 
logical classification as the grammar of geology, without which — 
" The student could no more make headway than he could read Horace or Virp;il 
without having first learned to construe in Latin." "Nomenclature," continues Mr. 
Taylor, is the ' slough of despond,' through which every man must wade ere he can 
cultivate the acquaintance of any science whatever. It is the Cerberus which guards the 
gates of its uuder-mysteries, the cipher whose knowledge unfolds the gathered wisdom 
of centuries; aft r this difficulty has been overcome, no man will stand up more for its 
utility or find it more serviceable than he who at first sight was about to turn a.vay with 
mingled feelings of disgust and despair ; and although such a classification is anything 
but perfect, and by no means to be relied upon as infallible, it serves as a clue to the 
mode of natural operations in bygone epochs. In short, its utility may be seen by the 
fact that it has been originated by those very men who wandered for years amid the com- 
plexities of geology, often without so much as an idea of their labours ; and these tech- 
nological terms are the results of their patient investigations and long years of experi- 
ence." 
"We cannot always agree with the author however, who, it is only just 
to say, follows closely to received opinions, some of which, it is well known, 
we have long been chsposed to contest. One of these points to which he 
adheres.is the old igneous origin of certain crystalline rocks : — 
" We may learn from this," he says, " that the various rocks of igneous origin owe 
their numerous modifications to the circumstances under which they have solidified, not 
to any difference in cheir origin ; the on'y changes being what they have lost or what 
