30 The Ash Bed at Meriden. 



must be studied out, and v/hen proper interpretation is given to 

 them the results will well repay the work that they have cost. The 

 direction in which further work can be profitably turned is first in 

 searching out all the possible outcrops that reveal contacts of the 

 traps with the overlying beds, in order to discover all the evidence 

 in regard to the origin of the trap sheets , and next to trace with 

 as much precision as possible the many faults that traverse the dis- 

 trict, which thus far have been detected chiefly in the neighbor- 

 hood of the trap ridges alone. The faults doubtless have an 

 extension of many miles, and some of them may even traverse the 

 valley obliquely from side to side. 



One of the most effective aids to such explorations will be the 

 preparation of a good map, in which I trust the Association will 

 feel a strong interest. The Massachusetts survey is now completed, 

 and its contoured map-sheets are in course of publication. The 

 field work of Rhode Island is also nearly or quite done. It is 

 most desirable that Connecticut should follow as rapidly as possible 

 in this excellent work, so that within a few years we may have a 

 reasonably correct physical map of southern New England, on 

 which the relief of the surface shall be duly portrayed. It will 

 then be a much less difficult task to advance in the interpretation 

 of the geological structure of the Meriden region. 



In case some of the members of the Association should desire 

 to read further on this subject, I take the liberty of referring them 

 to two articles now in course of publication: one in the Seventh 

 Annual Report of the U. S. Geological Survey, in which a 

 mechanism that has been suggested to explain the monoclinal 

 deformation of the region is discussed; an abstract of this was 

 printed in the American Journal of Science two years ago; 

 another describing the methods of work pursued by the Harvard 

 Summer School of Geology during its sessions of 1887 and 1888 

 for the week of its stay at Meriden, in which maps and detailed 

 itineraries of our excursions are given; this will appear in the 

 Bulletin of the Museum of Comparative Zoology at Cambridge. 

 A third paper is in preparation with the assistance of Mr. C. L. 

 Whittle, who has accompanied me on many visits to the valley, 

 in which the contacts of the trap and the overlying sandstones 

 will be especially considered in relation to the intrusive and 

 extrusive origin of the trap. 



Cambridge, Mass., December, 18S8. 



