1893. | NEW YORK ACADEMY OF SCIENCES. 77 
zoisite. If the limestone of the quarry could be traced to its 
contacts with the surrounding rocks, an undertaking that is pre- 
vented by the lack of outcrops, it is quite probable that it would 
prove to be an included piece caught up in an igneous mass, 
and that thus its isolated character would find a reasonable 
explanation. Professor Lesley surmises that the great develop- 
ments of limestone in New Jersey may lie far below the surface 
in Pennsylvania (Final Report, Vol. i, p. 111.) If this be true 
the limestone may have become involved in the igneous rock 
durirg the passage of the latter upward. 
Mr. G. K. Gizzert, of the U. 8. Geological Survey, exhibited 
photographs of a gaping fissure in the Aubrey limestone, 
twenty-five miles north of Cafion Diablo Station, Atlantic and 
Pacific Railroad, Arizona, and referred it to anticlinal rolls, as 
there was no faulting. 
Prof. Kemp remarked on its interesting relations to many 
mineral veins. 
Dr. Boron read a letter from a representative of the Smith- 
sonian Institute asking for information and analyses of mineral 
spring waters. 
January 30, 1893. 
Sratep MEeErTinG. 
Vice-President Dr. Boiron in the chair, about fifty persons 
present. 
The minutes of December 19th were read and approved. 
The following paper was then read, illustrated by experiments: 
FACT AND FALLACY IN THE BOOMERANG PROBLEM. 
BY C. H, EMERSON, WHITEHALL, N. Y. 
I advance the statement, that— 
The Australian boomerang does not possess a single desirable 
quality for an ideal boomerang flight, excepting only the gen- 
eral consideration that it is made of wood, and has its centre of 
gravity to one side of its main outline of figure. 
{ refer only to the returning boomerang, the principal 
features of which, as stated by various authorities, are: In 
general, the parabolic or hyperbolic curve ; in particular, the 
