28 NEW YORK STATE MUSEUM 



There are rounded aggregates which may represent an earHer gen- 

 eration, perhaps derived from a siHcate mineral of the pyroxene 

 or hornblende family. The talc nodules are frequently bordered 

 by veins of massive serpentine that appear to have resulted as a 

 reaction from contact of the talc with iron-bearing solutions. The 

 limestones at this place have undergone considerable disturbances 

 from regional compression since the deposition of the ores, mani- 

 fested by the brecciated and faulted condition of the deposits in 

 certain places and the flowage of the limestones into the fractures 

 so as to cement the broken and disjointed parts. The whole min- 

 eral association seems referable to the work of underground waters 

 which in a period of long-continued circulation have introduced and 

 deposited various ingredients. There is insufficient evidence, as 

 yet, to connect the mineralization with igneous agencies, and if these 

 have been a factor, they were no doubt connected with the granite 

 invasion, the only intrusive that has any prominence in the district. 



SEISMOLOGIC STATION 



The year's -records for the local seismologic station are given in 

 the accompanying table in conformity with the plan previously -used 

 in leporting the data. The list, it may be noted, includes only such 

 disturbances as set up prolonged and well-marked vibrational move- 

 ments, usually differentiated into phases — such as are referable 

 without much doubt to true tectonic shocks transmitted to the sta- 

 tion from more or less remote origins. Of almost daily occurrence 

 are brief or indistinct motions arising from various causes not 

 wholly explained, but these have not been taken into account in the 

 table. 



The number of individual tracings of earthquakes obtained within 

 the year ending September 30, 1912 was twelve, as compared with 

 nine in the preceding period, and nineteen in the year 1909-10. 

 This record seems to indicate a general falling off of late in seismic 

 frequency, at least with respect to the heavier shocks which are. 

 recorded mainly at the Albany station. There have been at the 

 same time few destructive disturbances ; within the past year, none 

 has transmitted vibrations that exceeded the capacity of the instru- 

 ment for registration. 



Since the station was established in ]\Iarch 1906, it has supplied 

 data in regard to ninety-eight individual shocks. In view of the 

 fact that the installation represents an early type, comparatively, 

 the results may be considered quite satisfactory. They sufficiently 

 demonstrate that the somewhat peculiar conditions existing in this 



