170 W. H. HOBBS REPEATING PATTERNS IN STRUCTURE OF LAND 



Wood bun 



the left. After crossing the highway the path again enters a narrow canyon 

 in the south Orenaug Hill between parallel cliffs to the east and west. For the 

 greater part of the distance that this fault is thus followed, the cilffs are seen to 

 be broken across by faults (north ± 54 degrees east) transverse to the one which 

 is being followed (north ± 5 degrees west). At such points, which occur with 



great regularity at distances of 

 about 100 paces (about 300 feet), 

 the cliff which has been dwindling 

 rapidly in altitude rises again to 

 near its former height, from which 

 it again falls away before the next 

 cross-fault is reached. It is also 

 noted that alternate faults exhibit 

 a larger throw, determined by the 

 difference in cliff altitudes, and 

 that minor faults are generally to 

 be observed at 50-pace intervals. 

 . . . Where the path enters the 

 canyon between the Twin Hills 

 the same structure is displayed in 

 the cliff facing west, but it is here 

 noted that when the cliff is high 

 on the west it is low on the east, 

 and vice versa — in other words, 

 there is a tendency for the oro- 

 graphic blocks to be upthrown in 

 alternate order corresponding to 

 the black and white squares in a 

 checkerboard. This is certainly 

 more than a local feature, for it 

 can be observed in the main west- 

 ern cliff of the same hill and else- 

 where, and the park drive, which 

 ascends the west twin by a very 

 uniform grade from the low south- 

 ern end, does so by keeping north 

 on the edge of one block until its 

 northern end is reached, then turn- 

 ing sharply across a fault to the block diagonally to the left, and after follow- 

 ing this to its end, utilizing the block diagonally to the right, and so on." ^^ . . . 



South Britain 



Figure 40. — Fault Blocks represented hy Out- 

 crojys of the upper Basalt Flow in the Pom- 

 peraug Valley, Connecticut 



(Hobbs, U. S. Geological Survey) 



The blocks which appear in figure 42 have been called the "unif' blocks 

 of the district because the smallest which could be conveniently mapped, 

 but these group themselves into composite blocks of similar pattern but 

 of larger orders. To quote again: 



81 Twenty-first Annual Report of the U. S. Geological Survey, loc. clt., pp. 107-108. 



