Page:The Journal of geology (IA journalofgeology11893univers).pdf/385
as well as in an east and west direction. The compression from the north and south has produced no dislocation, as no transverse faults have been discovered.
III. The rocks of this area have been very sharply folded. The types of folds are the unsymmetrical, with short and steep western and longer eastern limbs, and the overturned and sharply compressed fold with an easterly dipping axis. Reduced and ruptured underthrown limbs are not uncommon, but the evidence is that the extent and the throw of these minor faults is very slight. On the southeast flank of Tom's Hill this has produced the structure which Suess has called Schuppenstruktur. I would suggest, as an English equivalent of this term, weather-board structure.
IV. An important reversed fault, which has been termed the Housatonic Fault, has a northerly course along the eastern border of the area of schist ridges. Its course very nearly coincides with that of the Housatonic River for a considerable distance. The fault is traced from near Sheffield village to beyond South Canaan, a distance of about twelve miles. North of the Maltby Quarry it has the characters of an overthrust which increases in throw in going north, owing to the northerly pitch of the beds to the west. This has carried the Canaan Dolomite of the eastern or normal limb over the newer Egremont Limestone and Everett Schist of the western reversed limb. South of the Maltby Quarry the western limb has been upthrown, bringing Cambrian Quartzite and Gneiss against the dolomite. The dolomite has been extensively crushed and metamorphosed along the fault plane. Tremolite and white pyroxene have been extensively developed in the vicinity of the fault plane, and vein quartz has cemented the dolomite fragments together, producing a fault breccia.
It is very probable that the rapid alternations of pitch which characterize this area are not altogether unusual. It is only rarely, however, that the areal relations shed so much light upon the form of the crest lines and trough lines of folds. What has been set forth will, I think, show that evidences of general