OcTOBER 27, 1899.] 
Mr. Harwood, the taxidermist who accom- 
panied the expedition and by his work 
materially assisted Mr. Weld Blundell and 
Lord Lovat in forming so fine a series of 
birds. 
The mission despatched to Sierra Leone 
by the Liverpool School of Tropical Dis- 
eases for the investigation of malaria may 
be expected to send home some interesting 
specimens. Mr. E. E. Austen, the dipter- 
ologist of the British Museum, is a member 
of the party. He will, of course, give most 
attention to the special objects of the mis- 
sion—the connection of malaria with mos- 
quitoes—but, besides collecting these winged 
insects and acquiring valuable knowledge 
as to their habits and life histories, he will 
endeavor, as far as possible, to make col- 
lections of other groups, some of which are 
very incompletely represented in the Mu- 
seum. With reference to this question of 
mosquitoes and malaria it may be added 
that, owing to the official steps taken by the 
Colonial Office, the Foreign Office, the India 
Office, and the missionary societies, the 
British Museum will soon be in possession 
of a unique collection of these insects. As 
a result of the official circular issued on the 
subject, hundreds of mosquitoes have, we 
are informed, already arrived at the Mu- 
seum from every part of the British Empire, 
and these are belived to be only a very 
small portion of the consignments which are 
to follow in course of time. 
SOME NEW DATA FOR CONVERTING GEO- 
LOGICAL TIME INTO YEARS. 
WSHILE conducting the Union Pacific Ex- 
pedition through central Wyoming last 
August, I came upon what appears to be 
some valuable data for converting geological 
time into years. For a number of days we 
were encamped on the rim of Bates’ Hole, 
near Lone Tree Cr., and studied the Mio- 
cene beds, which are quite extensive in 
_ SCIENCE. 
607 
that region. Bates’ Hole is a vast depres- 
sion produced by the erosion of Tertiary 
beds and varies from six to twelve miles in 
width, and approximates twenty miles in 
length. In depth it varies from 500 to 1500 
feet below the rim, and is one vast expanse 
of rough and broken country, surrounded 
by bluffs so precipitous that up to this late 
date there has been but a single wagon road 
made to enter it from the southern end; 
and this is far from being ideal. The bluffs 
that surround this very singular depression 
take on all of the peculiar erosion topog- 
raphy seen in the ‘Bad Lands’ elsewhere, 
and in many respects surpasses any of the 
‘Bad Land’ scenery yet described. The 
Miocene beds are made of whitish bands 
chiefly and in the vicinity of Lone Tree Cr., 
there are many slopes of about 30° reaching 
upwards from the valley, and above them 
terrace after terrace of harder bands that 
represent the castle like erosion. The 
slopes, as well as in many places the bluffs, 
are partially covered with pine trees (Pinus 
murryana Eng.). The trees on the slopes 
are stunted, gnarly and knotty, and are 
strongly marked by their great struggle 
for existence under the most unfavorable 
conditions. The oldest of these trees 
vary in diameter from eighteen inches to 
two feet, and have been recording the rate 
of erosion on these slopes for about 300 
years. 
Erosion has been so rapid that the oldest 
trees are now standing upon their stilt-like 
roots, with their trunks elevated from the 
slope some three or four feet. The rate of 
erosion appears to have been uniform with 
the growth of the trees. The trunk of the 
sapling remained on the ground ; while the 
trunk of a tree six inches in diameter was 
often several inches above the surface, and 
the tree a foot in diameter was already upon 
stilts. On account of the shortness of our 
stay, absolute measurements of a large 
number of trees could not be made. Nor 
