DAVIS. — OUTLINE OF CAPE COD. 303 



XVL 



THE OUTLINE OF CAPE COD. 



By William Morris Davis. 



Presented ^larch 11, 1896. 



Summary. 



This essay attempts to restore the original outline of Cape Cod by reversing 

 the processes at work on the present outline (p. 308). In order to gain good 

 understanding of these processes, a review of previous accounts of tlie Cape is 

 introduced (p. 304), a general consideration of the development of sea-shores is 

 outlined (pp. 312-317), and the conclusions reached are applied to the problem 

 iu hand (p. 318). It is thus estimated that the land here once extended at most 

 two or more miles into the sea on the east, and that perhaps three or four thou- 

 sand years have been required for the retreat of the shore line to its present 

 position (p. 326). This period cannot, however, be taken as a full measure of 

 the time since the glacial deposits of tlie Cape were formed, for there is reason 

 to believe that the land stood higher than now for an unknown interval between 

 the building of the Cape and the assumption of the present attitude with respect 

 to sea level. 



The chief interest in the problem here discussed turns on the growth of the 

 great sand spit of the " Pro vincelands " northwestward from the "mainland" 

 of the Cape (p. 312), and on the protection thus afforded to the old cliffs of 

 High head. Brief account is given of the growth and waste of the Provincelands 

 (p. 323), and of the changes of the western shore line (p. 829). The essay closes 

 with some practical suggestions regarding the protection of Provincetown harbor 

 (p. 329), and some speculations concerning the future change of the Cape. The 

 consumption of the north arm — from the elbow to the hand — will probably 

 require about eight or ten thousand years (p. 331). 



Introduction. 



An excursion to Provincetown and the " mainland " of Truro on 

 Cape Cod with the students of the Harvard summer course in Physi- 

 cal Geography, in July, 1895, brought to my attention a number of 

 problems concerning the changes of outline suffered by the Cape. 

 These problems had taken rough shape on the occasion of a visit to 

 the peninsula several years ago. Supplementing the observations 

 made on the ground by a study of the Coast Survey charts and by a 

 review of what has been written on the subject, the following essay 



