THE BEACON SANDSTONE AT KNOB HEAD MOUNTAIN. 
47 
The Terra Cotta Mountains (Fig. 23). 
The Terra Cotta Mountains (B 6 , B 7 , B s ) appear to be composed mainly of sand- 
stone. They are abundantly riddled by dykes of dolerite which appear to have had 
considerable effect on the sandstone. The sandstone has a pale-pink tinge, and in 
the distance the hills have a clull-red colour, which contrasts strikingly with the 
dazzling snow and the yellow sandstone elsewhere. Some of the specimens from 
the moraine show that the sandstone has been altered to quartzite (697). The 
dykes will be mentioned in the next chapter when the dolerite-rocks are considered. 
Knob Head Mountain (B 9 ) (Plate V). 
The last spot where the Sandstone Formation was examined is on the east side 
of Knob Head, 30 miles from the South-west Arm or the hill Bj and about 
30 miles from the sea. Here 
a small outcrop, similar to 
that on the west of Beacon 
Height, is found at an eleva- 
tion of about 3500 feet. At 
a distance the whole lower 
portion of Knob Head Moun- 
tain appears to consist of the 
sandstone. The mountain, 
like the Beacon Heights, has 
a small cap of dark-coloured 
rock (dolerite), which is 
separated from a larger 
sheet below by a narrow 
and horizontal yellow band. 
This similarity in the summits of the three mountains makes it probable that all 
are parts of the same two sheets of dolerite. 
The sandstone-outcrop on Knob Head is less than a quarter of a mile long 
and about 100 feet high. Here again one bed was observed to have, all over its 
surface, cylindrical prominences like those described on page 43. At this spot, 
also, some beds contain alternate dark-coloured and light-coloured laminations, but 
nowhere did the rock show bands at all like the black bands found near the foot 
of Bj, nor was there found any structure in these dark laminae which would 
suggest organic life. 
