1889.] KEW YOKE ACADEMY OF SCIENCES. 15 



refer it 



observei 



Jersey. 



refer it to P. nitidum rather than to P. dichofomum. I have 

 observed and collected it frequently in the highlands of New 



October U, 1889. 

 Stated Meeting. 

 Vice-President Trotvbeidge in the chair. 

 Nine persons present (the evening being very stormy). 

 The following paper was read by title: — 



A review of the AMERICAN SPECIES OF THREAD-FINS 

 (POLYNEMID^). 



BY MR. PHILIP H. KIRSCH. 



It will appear in the Annals, Vol. V. 



The paper of the evening was then read, as announced : — 



THE ORIGIN OF DIAGONAL TRENDS IN THE EARTH's CRUST, 

 WITH APPLICATION TO THE PRODUCTION OF NORMAL AND 

 REVERSED FAULTS AND THE FOLDING OF STRATA. 



BY PROF. DANIEL S. MARTIN. 



(Abstract.) 



In studying the processes of evolution by which our globe 

 has assumed its present form and structure, notwithstanding all 

 that has already been traced out, there remain vast and varied 

 fields of investigation that have thus far baffled the acutest rea- 

 soning and eluded the most laborious search. Especially is this 

 the case with all those problems which concern the interior of 

 our planet, or the lower portions of its crust. What processes 

 are there going on at the present time, or have taken place in 

 the distant past, it is of course peculiarly difficult to ascertain, 

 partly from the inaccessibility of the region, and partly because 

 the conditions there existing are so widely different from those 

 at and near the surface, where alone observation is possible. 

 Yet so important and so intricate are the relations which connect 

 the interior with the exterior of the globe, that the subject forces 

 itself upon us in any attempt to study the history and structure 

 of the earth. At the same time, and for the reasons already re- 

 ferred to, it is a subject that affords peculiar scope for specula- 



