422 JOURNAL OF THE PLYMOUTH INSTITUTION. 
dock gates north-easterly limestone commenced again. " The 
northern side of the yard was once a steep lofty rock, high as a 
ship's masthead, and at its foot, about where the south building-slip 
now is, and toward the next slip, was a low neck of land across 
which the sea used to flow over at spring tides. The lofty rock 
being limestone of a different period of formation to any in the 
neighbourhood, and superior in quality to any thereabouts, it was 
in lapse of time all quarried away down to its present level." 
