208 Dale— Camhrlan Coiujlomemte of Ripton in Verttiont. 



Geol. Survey, caiue uj)oii a coarse coiiij-loinenite of this forma- 

 tion, coiitimied liis study of it in IDO-t, and revisited some of its 

 outcrops with Mr. Arthur Keitli in 1908. A preliminary 

 gcoloo-ic nuip of the northwest corner of tlie Brandon slieet 

 with a half mile strip east of it is shown in fio-. 1. Tiie trend 

 of the frontal part of the (rreen Mountain range is indicated 

 by the altitudes taken from the contour map. The pre- 

 Canibrian gneisses are not differentiated nor are the members 

 of the Cambrian series. Dikes of diabase altered to amphibo- 

 lite cut the gneisses but are not shown on the map. 



The age determination of the Cambrian was confirmed by 

 the writers discovery in 1903 in an outjutting mass of quartz- 

 ite on the east shore of Lake Dunmore (point marked F on 

 map) of pteropods determined by Dr. C. D.Walcott as Ilyolitli^s 

 of type communis and of spines of OUnellus. In 1890 Dr. 

 Waleott* mentioned his finding an Ostracod with a marked 

 I'esemblance to Nothozoe in a qnartzite bowlder on Sunset 

 Hill on the east side of Lake Dunmore, and his having previ- 

 ously found the same fossil in situ in the qnartzite east of 

 Bennington associated with Olenellus and Hyolithes irnpar. 



The qnartzite of the west ilank of the Green Mountain 

 range appears to be interbedded witli schist and this conglom- 

 erate forms the base of the formation. The conglomerate was 

 observed at the points indicated on the map, but its most 

 interesting outcrops are that about 1/2 mile E.N.E. of the 

 top of Monnt Moosalamoo and also that near the Chandler 

 house, 1 1/i mile N.E. of Ripton village. The cement of the 

 conglomerate is highly metamorphic, generally a muscovite- 

 quartz schist with more or less magnetite. More than half of 

 the pebbles are blue quartz and the rest are gneiss. At the 

 locality near Mount Moosalamoo the conglomerate lies close 

 to the pre-Cambrian gneiss and has a N. 15° W. strike, a 50° 

 to 80° E. dip, and a minimum thickness of 58 ft. Most of 

 the pebbles range from 3 to 6 inches in diameter but the 

 largest ones measure 10 X 8 in., 14 X 12 X 6 in., 20 X 9 1/2 

 in.^ and 23 X 16 X T in. This last is shown in fig. 2. At 

 Chandler's the conglomerate strikes N. 67° E. and dips 90°. 

 Here a pebble of blue quartz measures 76 X 57 X 30 in. and 

 over. Its major axis strikes N. 30° E. It might easily be 

 mistaken for a vein. See fig. 3. 



Bowlders of the conglomerate have been carried southward 

 by the ice sheet into the towns of Goshen and Salisbury. One 

 near the Dutton bi'ook schoolhouse, 4 1/4 miles south of the 

 Ripton-Goshen line, contains pebbles to 8 X 6 in. Another 

 bowlder, 20x10 ft., in Sucker brook about 1 1/4 mile S. 10° 

 "W. from the top of Mount Moosalamoo, consists of micaceous 

 quartzite containing three beds of conglomerate to a foot thick, 

 *U. S. Geol. Snrv., Tenth Ann. Eept., Part I, p. 268. 



