98 NEW YORK STATE MUSEUM 



the clay is often wet, probably through infiltration along the bed- 

 ding from some distant source. This wet layer has the usual 

 mobility of blue clay in that state and consequently tends to squeeze 

 out under pressure whenever there is opportunity for escape. The 

 conditions favorable to movement may develop unexpectedly. In 

 a city where excavations are going on the surface load is changing 

 all the time, so that caution should be exercised in the placing of 

 heavy structures upon the clay, especially if the sites are situated on 

 the edge or sides of the terraces. 



By the subsidence of a clay bank on the north side of Elk 

 street, west of Swan street, a few years ago, several houses were 

 rendered uninhabitable. The ground moved downwards along the 

 face of the bank, as the result of a slump at the base. The land 

 has since been converted into a park. 



The collapse of the Myers building on Pearl street in 1905 was 

 caused by a giving way of the foundations which rested upon blue 

 clay. The base of the sediments was below water level. Later 

 excavation for foundations of the new structure showed the lower 

 beds of blue clay to be thoroughly saturated. 



That extensive movements have taken place in past times in the 

 Albany terraces is indicated by the conditions encountered in the 

 excavations for the present Capitol. Some views of the founda- 

 tion work are preserved in the State Library, among them being 

 photographs of the banks of clay on the northern and western 

 sides which are of great interest. The bank exhibits evidence of 

 disturbance over a considerable distance, especially in the north- 

 western section where faulting and plication have taken place on a 

 large scale. One rather remarkable fault may be seen in the 

 accompanying illustration reproduced from one of the photographs 

 referred to. The fault brings the clays in juxtaposition with cross- 

 bedded sands that apparently are an uneroded remnant of an old 

 dune. The throw of the fault, so far as can be judged from the 

 photograph, exceeds 35 feet. The disturbance is of the type pro- 

 duced by flowage of the underlying layer, as described under class 

 4 in the general discussion. The ground within a short distance of 

 the fault falls away both to the north and east, in the latter direction 

 sloping down to the Hudson which here is little above sea level. 



Coxsackie. A subsidence of several acres of the terraced clays 

 near this place, which occurred in 1863, has been described by the 

 Rev. W. B. Dwight,^ who seems to have first visited the locality 



1 Am. Jour. Sci., 2d set., p. 12-15. 1866. 



