. Annual report. New York State Museum; Science; Science. GEOLOGY OF THOUSAND ISLANDS REGION 59. There is an occasional quartzite pebble along the contact, otherwise the sandstone is normal, and gives no sign of basal conditions. Around to the left the slope of the knob steepens. There are occasional bands of coarsely crystalline, purer quartzite in the schists which are far more resistant to weathering. On this steep front one such layer iprojects as a cornice with the sand-filling beneath, as shown in figure 3. Photographic attempts here proved wholly un- satisfactory. Besides the contacts o
. Annual report. New York State Museum; Science; Science. GEOLOGY OF THOUSAND ISLANDS REGION 59. There is an occasional quartzite pebble along the contact, otherwise the sandstone is normal, and gives no sign of basal conditions. Around to the left the slope of the knob steepens. There are occasional bands of coarsely crystalline, purer quartzite in the schists which are far more resistant to weathering. On this steep front one such layer iprojects as a cornice with the sand-filling beneath, as shown in figure 3. Photographic attempts here proved wholly un- satisfactory. Besides the contacts on larger slopes, of which the preceding are Fig> 3 A nearer view of a portion of the incton^flc fVic>t-/a ira o •nn-miViAt- n-P contact showing a local steep slope of the instances, mere are a numoer 01 hm and pro;jecting COrnice of an extra re- minor examples of the sort, chiefly sistant ^uartzite layer- as filled hollows of the limestone surfaces. A sand-filled hollow of the sort appears at the top of the limestone quarry near the Theresa boat landing, and is shown in plate 2. In the section there shown the hollow is about 6 feet deep and with twice that width at the top. Another example may be seen at the quarry just south of the Theresa depot, though the overlying sandstone is gone except for the small residual patch resting in the hollow so that its original size can only be guessed at. A considerable number of other examples have been seen, some merely sand-filled, others containing rock frag- ments as well. In all cases the cement is calcareous and the rock weak and easily removed. The above evidence of the character of the surface on which the Potsdam was deposited, is of precisely the sort so convincingly set forth by Wilson in his discussion of similar features in In New York these features are developed in a belt of considerable breadth across the strike, showing a great number of ridges and valleys, with patches of overlying Potsdam, and with the r
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