r30 NEW YORK STATE MUSEUM 



water now nestles. Loon lake, one of the larger lakes of this 

 class, has its shores entirely of these sands, which are widespread 

 around it. 



The possibility that there was a considerable lake, formed in 

 this belt back of the ice, must be borne in mind in further work 

 in the region. Its presence is not necessary in order to explain 

 the presence of the sands. These could have been formed equally 

 as well in small, local ponds at the ice edge. The question needs 

 more careful and painstaking work than it has yet been possible 

 to bestow on it. Did such a lake exist, it would be far more 

 deserving of the name " Lake Adirondack " than the water body 

 in the Lower Saranac and Ausable valleys to which the name 

 has been applied by Taylor.^ That there were lakes in these val- 

 leys held ap by the ice tongue which yet lingered in the Cham- 

 plain valley is beyond question. But it is not certain that they 

 were ever confluent, and they were not, strictly speaking, in the 

 Adirondacks. 



OBSERVATIONS IN THE ANORTHOSITE AREA 



During the hurried field work of 1898, hurried because of the 

 large area of which the writer's instructions required the map- 

 ping^ the bo'undaries of the large anorthosite area of southeast 

 Franklin county were followed and mapped, but the district was 

 not sufficiently crosscut to exclude the possibility of the presence 

 of considerable masses of other rocks within the heart of the 

 area. With this possibility in mind and for the added purpose 

 of ascertaining what signs of differentiation, if any, the mass 

 showed, the district w^as revisited in 1899. The result of the 

 work was to show that the area is constituted of anorthosite 

 throughout, except for small intrusions of later gabbro and a few 

 granite and syenite dikes of no great extent. It also showed a 

 certain amount of differentiation, though very slight in amount 

 when the size of the mass is taken into consideration. 



^Taylor, F. B. Am. geol. 1896. 19:392-96. 



