i8 NEW YORK State museum 



south part of Kecne,i about 8 miles southeast of the Ell)a Iron Works and 

 4 or 5 miles from Miller's in the same town. This bed, or rather vein, was 

 brought to light by a slide from the mountain which rises steeply from a 

 small sheet of water known in the vicinity by the name Long pond. The 

 v-ein is 20 to 40 feet wide, and occupies the highest part of the slide, being 

 nearly half a mile from the pond. It rises out of the hypersthene rock in 

 the form of an irregular vein or, more properly, mass. It has the usual 

 characters, but as a whole is coarser. Some parts furnish a fine blue, cal- 

 careous spar. A fact worth mentioning is that the blue portion is confined 

 to the surface, while the deeper situated is pale green ; but on exposure to 

 the light the latter also becomes pale blue. 



This locality furnishes undoubted evidence that the limestone is an injected 

 mass, or, in other words, a plutonic rock. The mineralogist will find in 

 this place a rich locality of pyroxene in all its forms and varieties. In 

 color it varies from the darkest green to nearly white. It is in fine, glossy 

 crystals, in perfect forms, and easily obtained by blasting the limestone. 

 Phosphate of lime in tolerable good crystals may also be obtained. Another 

 mineral which resembles idocrase is quite common ; it is in very small 

 crystals, but it has not been particularly examined. 



The limestone furnishes no tourmaline or feldspar; it is apparently more 

 in the character of a volcanic product, furnishing particularly those minerals 

 which are associated with lavas, as the pyroxene, amphibole, phosphate of 

 lime, idocrase etc., while in other places the same rock shows its analogy 

 to granite by containing tourmaline, feldspar, scapolite etc. Where the 

 primitive limestone furnishes the latter minerals, it is in beds more widely 

 extended, or much larger than in the former case. It is well known to 

 mineralogists that the narrow veins of granite are more bountiful in fine 

 minerals than the rock itself, when it occurs as one of the principal masses 

 over a widely extended tcrritorj^; in fact, under the latter form it is emi- 

 nently barren, except where it is traversed by veins of the same substance 

 of a much later period than the principal rock. In addition to the above 

 minerals, we have found large regular crystals of scapolite, some of which 

 now remain attached to the rocks, and are eight inches in diameter. 



The mass of limestone at Long pond belongs to one of those kinds which 

 must necessarily be quite limited in extent. It is bounded on two sides 

 by the hypersthene rocks, and runs south in its ascent up the mountain above 

 the slide, where it is concealed by soil, moss and the underlirush of the forest. 



The above quotation is of much interest, not alone because it 

 appHes to the hmestone of the Cascade lakes, but because it sets 

 forth Professor Emmons's views on the igneous or intrusive char- 

 acter of the Grenville limestones. The views are not so unreasonable 



1 The name Long pond was the original of the Cascade lakes. They are 

 also called Edmond's pond in Watson's History of Essex County, p. 421, 

 footnote, where it is stated that an avalanche in 1830 divided the old pond 

 into two. Professor Emmons mistakenly uses south for north, an error that 

 is very easy for one to make going from the southerly Hudson drainage to 

 the northerly flowing rivers. The pond is in the northern part of Keene. 



