DETAILED FEATURES OF COVEY HILL GULF 473 



strongly dissected by joints, which are opened for a width of 6 to 12 

 or even 24 inches. 



The lower part of tlie Gulf contains a lakelet some 900 feet long and 

 200 feet wide. Its elevation is 800 feet above the sea. Its depth is 

 great, as all the abundant talus, cleaving off the walls, is swallowed up by 

 the waters. Its depth is probably 50 feet to the level of a lower water 

 plane (at about 750 feet). Immediately beyond the lake the vertical 

 walls are abruptly replaced by a V-shaped gorge, with the falling talus 

 barricading the lake. This lower section has an older and distinct 

 history. 



Covey Gulf is relatively a very small trench compared with the channel 

 floor, of perhaps a mile in width, into which it is cut. Currents which 

 swept the drift from the surface of the outer channel could not possibly 

 have been confined within the narrow chasm, which shows a continuous 

 growth from its head. 



The features show that the Gulf was made by a small stream, with its 

 broadening due to frost action, the drainage basin having perhaps been 

 no larger than that of the plateau above during two or more episodes, 

 when the baselevel below was stationary as at 915 feet, thus facilitating 

 the widening of the canyon. Indeed, the disintegration of the sandstone 

 has been very rapid. In another locality I found that a small waterfall 

 had been cutting back into the same kind o£ rock at the rate of about a 

 foot a year, not to speak of the frost action. 



The terraces mark the abrupt lowering of the water in the higher part 

 of the gulf, the most important uniting to form the floor of the outer 

 gorge. Unlike the sharp Y-shaped upper portion of the main gulf, the 

 head of the outer gorge is somewhat rounded, a form apparently due to 

 the three or more streams which enter about its upper end. This feature 

 is common where streams unite to form coves in hillsides. The same 

 might be due to waterfalls, as in this case it is unlike the sharp V-shaped 

 head of the inner gorge of only a few feet in width, but it is improbable 

 that different forces make the upper ends of the two gorges, and the 

 multiplicity of the streams would account for the rounded form of the 

 end of one of them. 



The pond in the inner gorge is situated at a long distance from its 

 head, so that there seems to be no pronounced connection between it and 

 any cascade or rapids. The pond in the outer and shallower gorge is 

 drained by underground channels. About its lower end are slabs of rock, 

 absent from its upper margin. Their occurrence is easily explained, as 

 being due to loose blocks frozen in the ice and drifting down with the 



