160 MAURICE EWING AND A. P. CRARY 
Professor B. L. Miller of the Department of Geology, of Lehigh 
University, who recommended the location which was chosen for 
these experiments, has suggested that the structure of the limestone 
revealed by these results represents the buried valley of a pre-glacial 
stream. 
We are indebted to the Geophysical Research Corporation for 
the seismic instruments, to the Trojan Powder Company for the 
explosives, to Mr. H. S. Snyder upon whose property the experiments 
were carried out, and to Mr. A. M. Thorne, Jr., for assistance with 
the experimental observations. 
820 
