196 
The American Geologist. 
September, 1896 
Prof. H. B. Patton, in a paper read before the Colorado 
Scientilic Society Nov. 4, 1895, describes and illustrates bed- 
ded volcanic conglomerates and breccias in the upper Rio 
Grande valley. The depth of these volcanic formations he 
estimates at tliousands of feet. The rock is usually basic or 
andesitic, consists of pebbles, boulders, etc., imbedded in a 
tenacious, tine ash. Under rain and erosion th^ rock takes on 
fantastic shapes and stands in isolated columns and peaks. 
The Polar Cap of Mars. Mr. Percival Lowell has a dis- 
cussion of recent observations on the ice-cap of Mars in 
"Popular Astronoui}^ " for September, accompanied by a 
chart showing its shape and various sizes from June 3 to 
Oct. 5, 1894, and the intersecting canals. The center of the 
cap is about 6*^ excentric from the geographic pole of the 
planet, and its most northern extension (the cap is on the 
south pole) is to about latitude 55". The much discussed 
canals are explained as natural rifts in the cap along which 
the body of the planet is uncovered, or in which the oceanic 
waters enter. The entire cap is formed and melted annually. 
Facts about the 'Great Lakes. Mr. P. Vedel has tabulated 
the physical features of the great lakes in a late number of 
the Journal of the Western Society of Engineers as shown 
below. 
4J 
-a . 
03 
■« s ' 
s 
43 
•d 
— 
s 
cs E 
a 
* = P 
"2 
a 
o 
-a 
a. 
> - 
* « m 
Is 
=3 -J 
Si's " 
1l& 
ce P 
cc rt i • 
.-J 
<!i 
S 
m 
^ 
< 
r^ 
p.U*, 
fS 
ij 
< 
Lake Superior 
390 
70 
161) 
1300 
31200 
475 
1008 
602 
—406 
2X00 
51600 
82800 
St. Mary's river 
Lake Micliigan 
\h-A 
2^3 
5/ 
101) 
200 
53 
800 
1000 
} 41) 
:«5 
2 
4 \ 
85 
875 
202(10 
335 
870 
.581 
-289 
1290 
) 
Green Bay '. 
11.^) 
30 
15 
16 
21 
23 
260 
60 
17(K) 
.5(K) 
95 
75 
144 
234 
581 
.581 
H-437 
+347 
3(j 
7 
'• 37700 
(iOlOO 
Mackinac straits. . . . 
North cliannel 
11(1 
12 
IS 
220 
1400 
70 
240 
.581 
+341 
20 
; 
Lake Huron 
2!i(i 
5+ 
101) 
725 
17400 
210 
702 
581 
-121 
650 
■ 31700 
55700 
fxeorffian bay 
120 
■11) 
58 
390 
5200 
170 
4(i2 
581 
+119 
IVO 
\ 
3.5 
19 
1 
25 
29 
70 
90 
30 
410 
3800 
3400 
3s;« 
Lake St. (,'lair 
21 
575 
+554 
1 
:isi() 
Detroit river 
■M 
2 
3V„ 
54 
60 
1200 
1260 
Lake Erie 
25 
40 
.58 
590 
laxx) 
70 
204 
.573 
+369 
130 
22700 
32700 
Niagara river 
Lake Ontario 
31 
1 
9 
70 
611 
300 
:«) 
1«0 
40 
58 
600 
7300 
:m) 
738 
247 
—491 
4.0 
21600 
2S9;0 
760 
20 
95 
Totals 
5404 
95660 
5508 
174800 
270460 
The International Congress of Geologists. 
The general committee of organization has issued through 
Messrs. A. Karpinsky, president, and Th. Tschernyschew, sec- 
retary, a circular of information concerning the seventh ses- 
sion ()f the International Congress of Geologists. The session 
will be held at St. Petersburg in the latter part of the month 
