INTKODUCTION. 



Middlesex county is very irregular in outline, com- 

 prising an area, roughly approximated, of 830 square 

 miles. On the north it borders upon the Nfew Hampshire 

 line, an extreme point in Dracut reaching to latitude 

 42° 44' 12", on the east it extends (in Maiden) to longitude 

 71° 54' , closely approaching the sea coast ; on the south, 

 it touches lat. 42° 9' 30" (HoUiston) ; and extends westward 

 in a single tier of towns to long. 71° 1' 30" (Ashby). 



The highly diversified character of the county may best 

 be seen by a glance at the accompanying map and key. 

 The Merrimac river passes through the north-eastern 

 section, and the Concord through the centre, while all 

 portions are abundantly watered by numerous smaller 

 rivers and creeks. There are one hundred and thirty- 

 seven ponds, some of them of considerable size ; numer- 

 ous swamps of greater or less extent ; and salt marshes 

 along the tidal streams. The surface is very uneven. 

 Prospect Hill, Waltham, reaching a height of 482 ft. ; 

 Eeservoir Hill, Lincoln, 395 ft. ; Goodman Hill, Sudbury, 

 415 ft. ; Eeeves Hill, Wayland, 410 ft. ; Pegan Hill, 

 Natick, 408 ft. ; Nobscot Hill, Framingham, 602 ft. 

 The general elevation gradually rises to the highlands of 

 Townsend and Ashby, culminating in Mt. Watatic, a 

 granitic mass, 1847 ft. above the sea level, the highest 

 land in the county. 



The geological ages represented in Middlesex county 

 are three, viz. : 



1. The Cambrian, with slates and conglomerate; it 

 includes the comparatively low land within four to six 

 miles of Boston. 



