Terraces and River Valleys — Spencer. 167 
his best work, which has been fully recognized in a recent 
great monograph by Dr. Nansen. 
NOTE. — Reference was made on page . . to Prof. Broegger's 
citation of the occurrence of shallow water found at great depths. 
The dredgings were made at several localities near Spitzbergen and 
between Iceland and Jan Mayon. In the former region a consider- 
able number of Arctic shells were obtained at 656 and at 1333 
fathoms; and in the latter at 495, 729, 957, 1009, and 1309 fathoms. 
Dr. F. Nansen's conclusions that they have been transported by ice 
in recent time is extremely improbable, and this being the case 
Prof. Brogger says, "no other explanation is left than the supposi- 
tion of the former uplift of the sea bottom" to about 8400 feet. (loc. 
cited). 
ON THE ORIGIN OF THE CAVES OF THE ISLAND OF PUT-IN- 
BAY, LAKE ERIE.* 
By Edward H Kraus, Ann Arbor, Slieh. 
The island of Put-In-Bay. Ohio, in the southwestern 
portion of lake Erie, has for some time past been noted for 
its interesting caves. There are four, which are now open 
to the public. They are Danssa's. Kindt's, Perry's, and 
the "Crystal" or "strontian" caves. The first two are in- 
teresting because of their stalactites.^ The "Crystal'' cave 
is instructive on account of its beautiful crystallizations of 
celestite.t Perry's cave is the largest of the four and is 
perhaps over 200 feet in its extreme dimensions. The maxi- 
mum hight of this cave is about ten feet. 
The rocks of the island have been assigned to the 
Lower Helderberg epoch. These horizontally stratified 
rocks have been greatly disturbed in the immediate vicin- 
ity of the caves, but, as yet, no trace, whatever, of volcanic 
action has been noted at any point in this region. The 
peculiar condition, however, of the roof and also the floor 
of the Perry cave gives us a clew to the probable cause of 
the rock disturbances, if not of all the caves, of Perry's at 
least. 
* Read before the Philadelphia meeting of the Geological Society 
of America, December 29, 1904. 
t The stalactites of this cave have recently been studied by Puller in 
regard to their bearing upon recent land tilting. Science, N. S xx, IGl, 
1904. 
X Wright, a recently discovered cave of celestite crystals at Put- 
In-Bay, Ohio. American Goologiot. xxii. 261. 
Kraus, Occurrence and Distribution of Celestite-bearing Rocks, .■\meri- 
can Journal of Science, xix, 1905. 
