Page:The Journal of geology (IA journalofgeology11893univers).pdf/380
region. The fault probably extends a considerable distance farther to the southward but its course has not yet been traced. The northern course of the fault is indicated on the map.
Starting at the Maltby Quarry, where the surface rock on both sides of the fault line is Canaan Dolomite, and going northward, to the west of the fault line the generally northerly pitch carries the beds lower and lower so that Egremont Limestone is met before Sheffield is reached. On the east, however, no such pitch exists, and Canaan Dolomite is the surface rock for the entire distance. The Riga Schist has not been found in actual outcrop abutting against the fault plane and separating the two calcareous horizons, but this is explained by the absence of outcrops along the river valley. The map and section in Fig. 5 are introduced to indicate how the Riga Schist is believed to meet the dolomite at the fault line. This map is drawn on the same scale and has the same legend as Plate V. An examination of Plate V. will show how the hard Riga Schist of Miles Hill has caused a deflection of the Housatonic River to the eastward in that vicinity. The important easterly deflection which exists in the vicinity of the Canaan Camp Ground (cf. Fig. 5) is believed to be caused in the same way. The low area between the river and the road to the west of this bend is bare of outcrops, but Riga Schist is encountered on the road and covers a considerable area west of it. On the east of the river at this bend the tremolitic Canaan Limestone is encountered almost at the river's bank. There seems, therefore, reason for believing that in this vicinity the fault follows the river and that the two rocks abut against one another at the fault plane.
To the southward of the Maltby Quarry the fault is of a somewhat exceptional character, since the prevailing northerly pitch of the beds to the west of the fault line brings beds lower than the dolomite (First Cambrian Quartzite and then Cambrian Gneiss) to the surface in the Cobble. The upper limb of the fold is no longer the overthrown limb, but it is forced to a lower position. We have here, then, an example of a fault, which at the north is a rather steep overthrust with Canaan Dolomite over