Mineralogy and Geology. 287 
e ) 
strata are very different in magnitude from those of the Paleozoic age 
mity.”? 
r. Ramsay, in his address, next considers the Purbeck and Wealden 
Strata, his remarks on which he commences as follows: 
“We now come toa period in the geological history of the British 
marin zoic rocks in which, though not accompani 
parent physical disturbance, the break in the succession of species 
21. On the Permian Rocks of the Northwest of England, and their 
.B., ete., and Pro- 
or R. Harkvuss, F.R.S., F.G.S.—In this paper the authors propounded 
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conformably united with the Magnesian Limestone, or its equivalent, and 
form the natural upper limit of the Paleozoic deposits. They affirmed 
that thus a tripartite arrangement of the Permian rocks holds good in 
rla 
to exist in the Permian deposits of Germany and Russia, thus proving 
the applicability of the term Dyas to this group of rocks. 
e difference in lithological details of the Permian rocks of the north- 
West of England from those on the opposite side of the Pennine chain, 
Was next adverted to; and it was observed that, with so vast a dissimi- 
ny et are, however, somewhat comparable to the relations of the Lower and 
aad idovery rocks to each other, or to the variations in the subdivisions of 
Magnesian limestone, which were formed during minor oscillations of level. 
