MUSEUM OF COMPARATIVE ZOOLOGY. 79 



Grounds, and although not visibly traversing even the small measure 

 of the narrow block, it may be fairly identified as the anterior sheet, by 

 reason of its position. Its failure to make a continuous ridge may be 

 attributed to weakness resulting from the numerous small faults that 

 "were seen in the quarry. Farther along in the block, ledges of con- 

 glomerate and sandstone (5, 5') are found in appropriate position ■ but 

 their strike is seen to turn somewhat west of north, departing thirty 

 or forty degrees from the strike prevalent in the Lamentation fault 

 block, and thus helping to account for the abnormal trend of the 

 southern face of the Hanging Hills. The fault bounding the quarry 

 block on the northwest may be found by walking from the conglomerate 

 ledges (5) towards a wooded ridge (6), which is soon discovered to con- 

 sist of trap, and which must be regarded as the anterior sheet of another 

 block by reason of its attitude betwen the strong bluffs of Cat Hole 

 Peaks on the north and the conglomerate ledges (8) on the south. It 

 is overlain with fine red shales (7), whose strike is N. 45° W. and dip 

 20° N.E. ; no contact with the trap has been found here, though it 

 might be discovered by a little digging. The several breaks in the front 

 of the anterior ridge probably indicate small faults, and may in part be 

 associated with corresponding notches in the main sheet. This may he 

 called Cat Hole block, taking the name from -the deep pass in the main 

 sheet on its western side. The view of the block from the round hill of 

 conglomerate and sandstone (8) is especially valuable ; no point in the 

 district illustrates more clearly the necessity of working but the struc- 

 ture of every block by walking parallel to its length, instead of as usual 

 at right angles to the strike of the beds. The several members of the 

 quarry block can be located : the main sheet in the quarry ridge (1), the 

 anterior (4) alongside the Fair Grounds ; the conglomerate and sand- 

 stone ledges (5, 5') below. Cat Hole block is equally distinct ; the 

 main sheet in the castellated knobs at the end of the long ridges 

 (3 — 3) ; the wooded ridge of the anterior trap with the red shales 

 behind it ; and the conglomerate ledges below it, where we stand. 

 Farther west, Xotch Mountain block can be as well interpreted ; the 

 main sheet in its superb cliffs surmounting a long talus ; the anterior 

 (9), wooded again, west of us; and the lower sandstones in the rolling 

 ground farther south. 



Oblique valleys, undoubtedly located on fault lines, enclose Cat Hole 

 block on either side. Taking the anterior sheet as a guide to the dis- 

 location on these faults, and regarding its position in Cat Hole block 

 (6 — 6) as normal, we find it thrown to the northeast in the Quarry 



