66 NEW YORK STATE MUSEUM 



landing. On the weathered surfaces the rock is very rough and 

 deeply pitted due to dissolving out of calcite bunches. 



A very careful search southwest, west and north of the village 

 failed to bring to light any other exposure of either dolomitic 

 limestone or Potsdam sandstone than those above described, th'e 

 glacial drift masking the underlying rocks to the foot of the hills 

 (see map). Neither does the drift in this area anywhere carry 

 angular fragments of either sandstone or dolomite which Would 

 strongly suggest the existence of concealed ledges. In fact, even 

 rounded fragments are very rare. An angular fragment of typical 

 Trenton limestone with fossils just west of the southern end of 

 Thurman pond suggests such limestone in place, either now or 

 just before the Ice age, not farther south than the vicinity of 

 Schrooh Lake village. 



Age of the dolomite. A diligent search through the dolomitic 

 limestone of all the exposures failed to reveal any remains of 

 organisms. Kemp, in his report of 1895, likewise states that he 

 was unable to find fossils. This absence of fossils, combined with 

 the isolation of the limestone at Schroon Lake, renders it prac- 

 tically impossible to correlate very definitely or -determine the age 

 of this limestone. -G. E. Hall, in the paper above mentioned, makes 

 the following very brief statement: "At Schroon Lake village the 

 Chazy limestone occurs with fossils. The outcrops are not exten- 

 sive, being covered by a sand clay deposit." With Hall, however, 

 consideration of the Schroon Lake outlier was an incidental matter 

 and more than likely, on the basis of general resemblance, the 

 Schroon Lake limestone was classed with the fossiliferous Chazy 

 limestone of the Champlain valley, the fossils having been assumed 

 to be present 



Kemp 1 notes the close resemblance of the Schroon Lake lime- 

 stone " to the cherty magnesian limestones that are undoubtedly 

 Calciferous (in .age) and nonfossiliferous on Lake Champlain," 

 and with some hesitation he correlates them. The writer believes 

 Kemp essentially correct in this view. But the. old Calciferous 

 formation, many hundreds of feet thick in the Champlain valley, 

 was then considered to be wholly Ordovician in age, with cherty 

 beds in the lower portion. 



As a result of more recent work, important changes of view 

 regarding the old Calciferous formation have taken place, these 

 changes being concisely stated by Gushing 2 as follows : " The name 



*i5th Annual Rep't N. Y. State Geol., 1895, p. 597. 

 2 N. Y. State Mus. Bui. 169, p. 42. 1914. 



