332 Correspondence—MUr. A. J. Jukes-Browne. 
their divisions must differ in the maritime and inland regions, and 
that hard and fast lines should not be drawn at the confines of sys- 
tems, nor widely different formations of the same age reduced to an 
arbitrary uniformity of classification not sanctioned by nature. It 
was also inferred that the evidence pointed to a permanent con- 
tinuance of the Atlantic basin, though with great changes of its 
boundaries, and to a remarkable parallelism of the formations 
deposited on its eastern and western sides. 
4. “On a Hornblende-biotite Rock from Dusky Sound, New 
Zealand.” By Captain F. W. Hutton, F.G.S. 
The rock is of eruptive origin, and is associated with Archean 
schists and gneisses. It is compact, crystalline, of a dark-green 
colour, and sp. gr. 8: 00—3:07. It is composed of two minerals in 
nearly equal proportions, one of which, a black mica, has the two 
optic axes nearly coinciding. The other mineral is of a pale bluish- 
green colour, and moderately dichroic ; it shows an aggregate polari- 
zation of rather coarse grains, with here and there distinct crystals 
of considerable size. Often one side of a crystal shows a single 
twin, while the other side is polysynthetic. The optical characters 
are those of the monoclinic system, and further investigation proves 
these crystals to be hornblende. The mineral which shows aggregate 
polarization is either crushed hornblende or some altered form of it. 
CORRESPONDENCE. 
——E———— 
THE CORRELATION OF MIDLAND GLACIAL DEPOSITS WITH 
THOSE OF LINCOLNSHIRE. 
Str,—It is certainly very desirable that the Glacial Deposits 
should be correlated with one another, but I do not think any reliable 
results will be obtained by comparing the descriptions and conclu- 
sions which have been published by Mr. Deeley and myself. We 
have necessarily looked at the beds from different points of view, 
and I had hoped that Mr. Deeley would have made himself person- 
ally acquainted with the tract which lies between the areas we have 
respectively studied before suggesting anything in the way of cor- 
relation. 
He thinks that his classification into Older, Middle and Newer 
Pleistocene might be adopted for Lincolnshire, though the only 
“Older Pleistocene”? deposit known to him in that county is the 
quartzose sand of Gelston. He suggests, however, that some of the 
clays classed by me as Newer Glacial may really be older than the 
Chalky Boulder Clay, and he apparently finds great difficulty in 
accepting the occurrence of such Newer Glacial Beds at elevations 
approaching 400 feet. I will only reply that there are many places 
where he may walk from the eastern plain to the top of the Wold 
over a continuous sheet of the same kind of Boulder Clay ; but when 
Mr. Deeley can record any facts which seem to support his idea, I 
shall be quite ready to discuss thei. 
As regards the Gelston Sand, I must point out that this is an out- 
lying patch, and there is no local evidence to show whether it is older 
