TIIK LIMESTONE OF KEENE TYPE LOCALITY. 259 



To the eastward, on the adjoining Woods farm, is located tlie Woods 

 mine, of the same general character as the Hale and also in limestone. 

 The limestone at this opening is likewise contained in the rock pre- 

 viously called granulite, and tlie true anorthosites are prohably not far 

 distant. 



The geologic relations of this small area of limestone are interesting 

 and important. It is a pyroxenic limestone, not essentially different 

 from the ophicalcites elsewhere. The presence of garnets in it is, how- 

 ever, exceptional, and their close intermingling with the pyroxene is not 

 seen elsewhere in this rock. In no other instance is there a magnetic 

 ore-body actually in limestone in the Adirondacks and only one other in 

 the contact with this rock, as will be seen later in referring to Cascade- 

 ville. In fact the only other case known to the writer in the eastern 

 part of the country is at Franklin Furnace, New Jersey. Rocks much 

 the same as the socalled granulites have in one or two cases been ob- 

 served elsewhere on the east side of the Adirondacks, but not in associa- 

 tion with limestones. A very similar exposure was found in the town 

 of Schroon, where it was an undoubted contact facies of anorthosite on 

 gneiss. It has the same untwinned feldspar and green pyroxene as the 

 Keene rock and creates the same general impression. It has some 

 hypersthene and hornblende intergrown with augite, but lacks garnets. 

 Very similar rocks have been discovered l)y C. H. Smyth, Jr., on the 

 west side in situations where they seem undoubted contact phases of the 

 anorthosites. In the Keene exposure they are therefore to be regarded 

 as ai>ophyses of the neighboring anorthosite mass and as having been 

 intruded in the limestone. While it is diflicult to draw the line in this 

 district between the possible effect of regional metamorphism as a cause 

 of the minerals distributed through the limestone and the contact effects 

 produced on a grand scale by tlie anorthosites, yet the presence of gar- 

 nets and magnetite is here exceptional, and it is therefore natural to 

 suppose that the igneous rocks had their influence in bringing them into 

 being. 



The shading of a lime-soda rock like anorthosite into one more or less 

 rich in orthoclase, or at least soda-orthoclase, and with abundant micro- 

 perthitic feldspar affords also difliculties of explanation, but on the whole 

 the geologic relations in the exposures and the parallel cases elsewhere 

 indicate that this explanation is preferable to the one that the granulite 

 represents a gneissic rock interbedded with the limestone. 



TIIK CALCITE VEINS. 



The views of T. Sterry Hunt, cited at the outset, suggest that tiu' lime- 

 stones at Port Henry are a great veinstone or series of veinstones, with 

 the broken fragments of the; wall-rock contained in the calcareous mass. 



