352 The American Geologist. December, 1894 
with the dawn, myself and nephew were at our work of triangulating. 
Finally, having completed the survey and obtained geological speci- 
mens of greal interest, we joined ourselves to the world again. 1 shall 
calculate my observations, make drawings of ground plan and elevations 
and include them in my report to Dr. Jackson, and. through him, to the 
government, that, if they are found worthy of it. they may be published. 
I need hardly say thai such a curiosity, in such a climate, deserves a 
visit from the C'incinnatians during the hot months. Within half a 
mile is a boat harbor, a fine camping ground, a ml st ill another halt' mile 
along the beach is the Chappel rock, and still nearer a. cascade. Beyond 
this again is a cascade, leaping from the top of the pictured rocks clear 
into the lake, and blowing a blast of wind in all directions from where 
it strikes the water sufficient to propel a sailboat. 
The grand portal is less extensive than the mammoth cave, being a 
mere fraction of it: but it has several compensating beauties. It has a 
light and tine breeze, and it is, at the same time, as cool. You arrive at 
all of its beauties without fatigue, and enjoy, through its open arches, 
the most extraordinary landscapes. Through the grand portal you see 
only the shoreless lake. Through the western opening of the cross arch 
a limited but magnificent view of the lake, the pictured rocks overhang- 
ing its dark blue waters, on whose surface, when calm, those rocks are 
reflected into a symmetrical counterpart of the original. Through the 
eastern wing is seen also the lake and pictured rocks, dying away in 
we'll marked perspective, as one point sinks behind the other, to the 
distance of 10 miles. In the course of this perspective is the cascade id' 
Chappel river, the Chappel rock and the cascade of the winds. This 
cross arch is 500 feet long and so straight that light is seen through it 
from one side to the other. 
Mr. Schoolcraft passed through it with his boat, but the lake having 
fallen about four feet it is now barely dry, and the only entrance by 
water is by the grand portal. 
Dr. Locke identified the Blue limestone on St. Joseph's 
island, and the Cliff on Drunimond island. The latter he traced 
westwardly to great Bay de Noquet. From the dip and the 
succession of the various formations between St. Joseph's and 
Drunimond islands he concluded the red sandstone at St. Ma- 
ry's falls belongs beneath the Trenton and Cincinnati lime- 
stones, "and is therefore rather the older red sandstone than 
the new red sandstone." This was contrary to the opinion of 
both Jackson and Houghton. The limestone (the Trenton) 
which he found on the west side of little Bay de Noquet he 
rather thought belonged to the Carboniferous, and iinagineda 
fault-plane running north and south under little Bay de No- 
quet in order to bring about such a position for a much younger 
limestone, as he knew of no such rock beneath the Blue lime- 
