62 
The American Geologist. 
January, 1896 
thin bands of black graphitic slates, with good, slaty cleavage, and 
interstratified with the other two varieties. No fossils were found, 
although careful search was made. 
The limestone is called the “ Glacier Bay limestone.” It is dolomitic, 
and for the most part extremely pure, containing only a trace of insol¬ 
uble matter. Fossils were rare and so damaged by metamorphism as 
to be unrecognizable. But in 1893 a fossil coral was brought from the 
reo-ion by Prof. Stevenson, which had certainly been derived from the 
limestone. It was identified by Prof. H. S. Williams as a species of 
Lonsdctleia, and was regarded as demonstrative of the Carboniferous 
age of the beds. 
The quartz-diorite is a homogeneous rock, consisting of white 
plagioclase, with frequent thin prisms of hornblende, and occasional 
biotites and some quartz. A contact was found between it and the 
argillites which seemed clearly an irruptive one. Other contacts oberv- 
ed by Dr. Reid with the limestone indicated contact metamorphism. 
The diorite is a more basic rock than the quartz-diorite, and is found 
in the moraines. It has probably come from the mountains, which 
have yet proved inaccessible. The crystalline schists embrace mica 
schists and actinolite schists and were obtained from erratic blocks. 
The diabase dikes have all been intruded since the metamorphism of 
their wall rocks and are the latest rocks in the region. Mr. Cushing 
(fives a detailed comparison of these rocks with other Alaskan sections, 
noting many parallel features and some contrasts. The paper concludes 
with a detailed petrographical description of the crystalline rocks. 
The second paper of the evening was b y Heinrich Ries, on 
“ The geology of Orange county, New York.” Mr. Ries gave a 
resume of the results obtained by him while in the field the 
past summer under Prof. James Hall, state geologist, to whom 
the report will be made. The paper was not intended for 
publication, but was illustrated by numerous lantern views 
and geological sections. 
The third paper was by Theodore G. White, on The 
faunas of the upper Ordovician strata at Trenton Falls, New 
York.” This paper was illustrated by numerous lantern 
views from photographs. 
Mr. White described the results of a visit to this, the typical locality 
of the Trenton formation, and of detailed study of the faunas of each 
stratum of the limestones at Trenton Falls and Poland, Oneida county, 
New York. The work was undertaken in connection with a doctorate 
thesis on the Trenton faunas of the Lake Champlain valley, which will 
be submitted in the spring to the faculty of Columbia College. The 
faunal lists at Trenton Falls will be published in full in the Transac¬ 
tions of the Academy of current date. 
By making use of conspicuous and constant layer's as datum planes, 
the thickness of the beds in the Trenton Falls gorge was found to be 
331 f ee t. On the same creek, three miles below Poland, underlyhjg 
strata were found as follows: 
Black River limestone..11 feet, 9 inches. 
‘ ; Dove ’’ limestone...5 “ 1 inch. 
Calciferous strata..8 
Various peculiar distortions of the beds in the Trenton Falls gorge' 
was also shown and discussed. 
The fourth paper of the evening by J. F. Kemp and T. G. 
White, “ Additional notes on the distribution and petrography 
of the trap dikes in the Lake Champlain region,” was post¬ 
poned until the next meeting, on account of the lateness of 
the hour. J. F. Kemp. Secretary. 
