GEOLOGY OF THE PARADOX LAKE QUADRANGLE 



483 



manite gneiss represents shale, and the graphitic rock the sandstone 

 of the same series. 



Shaly quartzite. Overlying the garnet-sillimanite gneiss of Graph- 

 ite is a quartzite, impure and feldspathic, in some localities sheared 

 into a schist. It occurs also in the bed of the brook at the extreme 

 southeastern corner of the quadrangle. Several fault lines can be 

 seen along the brook, the most notable one being at the Hague 

 gristmill [see pi. 8, fig. 1]. 



The exposure at the graphite mine in the village of Graphite is 

 separated from an eastern one at the Lakeside mine, Hague, by a 

 hill of syenitic gneiss and by drift in the valley. The uniform strike 

 for both localities is n. 65 e. and the dip of variable amount, 

 toward the southeast. The eastern exposure would hence appear 

 to be the upper one, but the frequency of faults makes its position 

 uncertain. Some layers at the extreme eastern edge of the map 

 are conglomeratic. 



Summary of stratigraphic relations. The oldest rock is the horn- 

 blende gneiss ; conformably above this is limestone ; interbedded with 

 both is the biotite schist. Above these, possibly with an uncon- 

 formity, is the sillimanite gneiss ; interbedded with it as a local 

 variation is shaly quartzite ; above these, graphitic sandstone. 



Intrusives. It has long been recognized that the core of the 

 Adirondacks consisted of a rock of the gabbro family which has been 

 named anorthosite. It has also been long recognized that gabbros 

 of later age than the anorthosite were widespread. Of late years 

 another type of intrusive has been recognized by Dr Smyth on the 

 west and by Prof. Cushing on the north, and has since been found 

 throughout the region, the most common phase of this rock being 

 a syenitic one. All of the above types occur in the Paradox Lake 

 quadrangle. A fourth variety which has not yet been recognized 

 as a distinct type, although phases of it have been described, is also 

 present in large amount in this quadrangle. This will be here 

 called the Pharaoh type from the mountain where it is best exhib- 

 ited. It presents the general mineralogy of a granite, but appears 

 to be a different rock and older than the granite found in the 



