The diurnal tides at Pitlekaj, Point Barrow, and Flaxman Island are, as noted below, also too small to permit of this hypothesis.

The smallness of the diurnal tide in the cases cited can probably be explained on no other assumption than that of obstructing land masses extending over a considerable portion of the unknown region of the Arctic Ocean.
No further attempt will be made here to prove the necessity for a tract of land, an archipelago, or an area of very shallow water situated between the present Arctic Archipelago and Siberia.

A brief discussion of this question, together with a tidal map of the Arctic Regions, will be found in a paper about to be issued by the Coast and Geodetic Survey and which has been already referred to.

A few pertinent facts may, however, be mentioned.
(1) At Point Barrow, Alaska, the flood stream comes from the west and not from the north, as the hypothesis of an extensive, deep polar basin implies.
(2) The semidaily range of tide at Bennett Island is 2.5 feet, while it is only 0.4 foot at Point Barrow and 0.5 foot at Flaxman Island, Alaska.
This indicates that obstructing land masses lie between the deep basin or channel traversed by the _Fram_ and the northern coast of Alaska.
(3) The observed tidal hours and ranges of tide show that the semidaily tide is not propagated from the Greenland Sea to the Alaskan coast directly across a deep and uninterrupted polar basin.
(4) The observed ranges of the diurnal tides at Teplitz Bay, Franz Josef Land; at Pitlekaj, northeastern Siberia; and at Point Barrow and Flaxman Island have less than one-half of their theoretical equilibrium values based upon the assumption of an uninterrupted and deep polar basin.
In addition to these facts are the following items which have a bearing upon the shape and size of this unknown land: The westerly drifting of the _Jeannette_.
The westerly drifting north of Alaska observed by Mikkelsen and Leffingwell.
The existence of Crocker Land.
The shoaling indicated by a sounding of 310 fathoms taken in Lat.

85 deg.
23' N.
The eastward progression of the tide wave along the northern coast of Grant Land as shown by observations at Point Aldrich, Cape Sheridan, and Cape Bryant.
The great age of the ice found in Beaufort Sea.
Items of some importance in this connection, but which cannot be regarded as established facts are: The probable westerly courses taken by casks set adrift off Point Barrow and off Cape Bathurst, the one recovered on the northeastern coast of Iceland, the other on the northern coast of Norway; The question suggested by Harrison whether or not enough ice escapes from the Arctic to account for the quantity which must be formed there if one were to adopt the assumption of an unobstructed polar basin.
Taking various facts into consideration, it would seem that an obstruction (land, islands, or shoals) containing nearly half a million square statute miles probably exists.