273 
[Annual Meeting. 
1891.] 
will be used to illustrate the relations of animals to the earth as 
shown by the position of the centre of gravity in their bodies. 
The topographic model of the Island of Oahu has been finished 
by Mr. James Emerton and was exhibited at one of our meetings 
during the winter. A case was built for its reception in the hall 
and now stands against the wall in one of the windows. 
The Gulick collection of Achatinellinae has been arranged and 
put in order by Mr. Henshaw and tables showing the distribution 
of different species drawn up by him. The Curator has spent 
considerable time in following out the series and in trying to trace 
the history of the supposed lines of evolution and migration. 
No literature exists which can guide one through this labyrinth, 
and it is not only necessary to do this original work, but to corre- 
spond with various experts in order to obtain reliable information 
with regard to the habits and characteristics of the animals of 
the different species. 
Geology. 
The Guide to the petrographic collections, including both 
lithology and petrology, is finished, and it is to be hoped that it 
may be speedily published. The accessions have been few in 
number but are valuable additions, because they consist chiefly 
of material collected by Prof. Crosby for the New England col- 
lection. 
They include, among others, a very instructive example of 
contorted and eroded gneiss from Paris, Me. ; specimens from 
Bland ford, Mass., showing the derivation of soapstone from 
actinolite rock ; and a complete series of the kaolin or residual 
clay of Blandford, showing its derivation from the coarse pegma- 
tite or vein granite. Prof. Crosby has published during the 
year a full account of this interesting remnant of the sedentary 
detritus which probably covered all New England in pre-glacial 
times as it now does the southern states. There is also a com- 
plete series of residual clays from the District of Columbia to be 
used in the Dynamical collection. These illustrate a communiJ 
cation made by Prof. Crosby at a recent meeting of the Society 
on the Colors of Soils. There is also a series of specimens of a 
finely stratified or banded glacial clay from the vicinity of Con- 
cord, N. H., showing very clearly, in the regularly alternating 
light and dark layers, that the deposition of the clay went on at 
18 Aug. 1891. 
PROCEEDINGS B. S. N. H. 
VOL. XXV. 
