71 
black and white, and a perfect Lae eae may thus be secured. 
very finest veins are brought into view in this way, a 
features which are not visible to ie unaided eye, in the a 
are frequently clearly shown in the photograph. Sa 
taken by this process were — to the confer 
The following statements by Mr. Ridgway of ce ame States 
Department of Geology give detail the method employed in 
securing these photographs: ‘‘The fine results obtained are 
largely due to the unusually good negatives made in our labora- 
tory and to the superior quality of velox paper used in printing. 
Average and thin negatives are printed on ‘Regular Velox’ and 
intense negatives are printed on ‘special Velox,’ a paper made 
anand for the Survey. In regard to the method used for 
oduc 
producing the vapor-coating on specimens: In carrying out the 
process now used, two small bottles containing the coating liquid 
are required. One contains hydrochloric acid, and the oth 
ammonium hydrate. These two ae are securely held to- 
gether with a wooden yoke and glass tubes are inserted which 
connect them in such a manner that when blown into at one end 
the fumes of the two chemicals are united, cane chloride of 
ammonium salt, which is deposited on the specimen fter 
the specimen has been photographed ae oo or coating, 
is readily removed by moisture of the brea 
In the second paper Dr. Hollick referred to the collections of 
fossil plants made by him in 1903 in Alaska, and those made 
subsequently by other parties in the a of the United States 
Geological Survey, and to his recent work of arranging, studying 
and describing the specimens. 
Heretofore no Cretaceous flora has been described from Alaska, 
and only a very few Tertiary species. The results of the recent 
work indicate the differentiation of at least two Cretaceous and 
two, or possibly three, Tertiary floras, suaegin several 
hundred species, a large number of which are new spec 
Considerable difficulty was experienced in trying to ie 
these floras, exactly, with known fossil floras from other parts of 
the world, for the reason that they contain so many new species 
