230 



CURTIS AND W00DW0RTH 



The following table gives the geological horizons recognized 

 at Nantucket and the corresponding topographic features which 

 are represented in the legend of the model by separate colors. 



I am indebted to Professors Shaler and Davis, and Mr. M. S. 

 Jefferson, for helpful criticism on this model, and especially to 

 Mr. J. B. Woodworth, whose valuable aid has much increased its 

 merits. G. C. Curtis. 



A SKETCH OF THE GEOLOGY 1 



The island of Nantucket, which has been made the subject of 

 a model by Mr. Curtis, is one of the most instructive portions of 

 the terminal moraine of the last ice epoch in North America, 

 because it is the most distinct and isolated of these glacial accu- 

 mulations. Set in the waters of the ocean far to the south of the 

 morainal belt of Cape Cod, and distant nearly its own length 

 from the neighboring island of Martha's Vineyard, the peculiari- 

 1 Written by J. B. Woodworth at the request of Mr. G. C. Curtis. 



