ELIZABETHTOWN AND PORT HENRY QUADRANGLES 85 



found, rolling over in a low anticline and dissolved out into small 

 caves. Anorthosite was found higher up after an interval of 

 sedimentary gneiss. 



In very much the same way as depicted here^ the Grenville is 

 found in the Ausable quadrangle to the north; the Lake Placid to 

 the northwest; the Mt Marcy to the west, and the Paradox lake 

 to the south. 



Collectively viewed one can not form any other broad and com- 

 prehensive conception of the areas, than that they once formed an 

 extended and ancient formation which was invaded by the over- 

 whelming amounts of igneous rock, in the deeper seated portions 

 of a great center of eruptive activity. iSo extended are the masses 

 of the latter that only fragments of the Grenville remain with slight 

 suggestions of original structure. So far as these can be deciphered 

 however, the dips are prevailingly moderate and the ancient sedi- 

 ments appear to have been folded or tilted to only a moderate 

 degree. 



Areal distribution of the granites and related types. The chief 

 area of these rocks is in the southeastern corner of the sheet. They 

 constitute the abrupt fault block of Bulwagga mountain, and extend 

 westward from its escarpment for nearly 3 miles. 



The more northerly exposures are relatively small, numbering but 

 three in all and believed to be in the nature of dikes or bosses. 



North of the east end of Crowfoot pond in the ridge a quarter 



of a mile from the water's edge there is also a development of 



■ granitic gneiss, but it is so closely involved with the syenitic series 



that it has been regarded as an extreme phase of these rocks and 



has not been colored differently. 



At best these rocks are minor members in the local geology, and 

 the uncertainties of their relations have been set forth in the gen- 

 eral description. 



Distribution of the anorthosites. The anorthosites make up the 

 western third of the area and are the rock of the high mountains. 

 They sweep around on the north and constitute the northeastern 

 corner. This portion sends a prong southwestward nearly to Mine- 

 ville and embraces in its sweep an area of the other formations, 

 including the Stacy brook Grenville. The anorthosites extend into 

 all the bordering quadrangles in New York; except the Ticonderoga 

 on the south, where they, fail entirely. From the Elizabethtown 

 quadrangle they cross a few miles into the Paradox lake, but then 

 cease and are, so far as known, seen no more in the extended Pre- 

 cambric area still farther south. They culminate in the Mt Marcy 



